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Glossary of plant terms

Search our dictionary of 3,300 botanical and plant-related terms – the largest online.
Or browse the descriptions and definitions using the A-Z.


Means "bag-shaped" in Latin.

saddle graft

A method of grafting where the scion has only one terminal bud and it is bound onto the rootstock until a graft union forms.


Shaped like an arrowhead.


Means "arrow-shaped" in Latin.


A name given to an arboretum devoted to willows.


Means "willow-leafed" in Latin.


Means that it contains salt (sodium chloride), usually referring to water sources or soil.

salt damage

Salt prevents the normal uptake of moisture and nutrients. Leaves develop brown patches and curling. The leaves may be undersized and fall prematurely. Stems may die-back. Sycamore, maple, spruce, alder, lime and plane are amongst the plants that can be affected.


This is another name for potassium nitrate which is also known as nitrate of potash.


A medium containing large pores and gritty particles so that it is free-draining and contains few nutrients. It may be used as a rooting medium for cuttings and seeds but once roots have formed the plantlets need to be planted on. Sand may be mixed in with other media to improve drainage.


Means "blood-red" in Latin.


A general term referring to the liquid substances found in plant tissues. The sap rising from the roots contains a weak solution of various chemicals absorbed by the roots, and being transported (via the xylem in the vascular tissue) to the shoot and leaves prior to the process of photosynthesis. The phloem transports a solution of sugars and other compounds to the roots and tissues such as storage organs and fruit.


Refers to a young tree that has not yet developed heartwood.


A plant which derives its food wholly or partially in the form of complex molecules from dead or decaying organic matter. eg fungi growing on dead wood.


Referring to a saprophyte which derives its nourishment form dead or decaying organic matter.

sap vacuole

Many plant cells contain an small pocket of sap, which in part helps to maintain the turgidity of the cell. The sap is a complex solution of various chemicals.


Refers to a plant which produces long thin stolons.


Means "cultivated or planted" in Latin.


These are extensive open tropical grasslands, with scattered trees and shrubs. Savannas naturally covered large areas of Africa, North and South America and northern Australia. The soil is generally acidic, sandy and often with an impermeable pan not far below the soil surface which restricts the penetration of tree roots. The savanna grasslands of Africa such as the Serengeti are famous for their wildlife. Most savannas can only sustain low-density grazing by cattle, and if ploughed up are susceptible to vigorous soil erosion. In some areas such as the Gabon and Congo where there is higher rainfall, the savanna sustains woodlands.


A name given to several species of fly-like insects. (Slugworm is the name given to sawfly larvae, since they resemble small slugs.) An example is the rose sawfly which inhabits rolled up rose leaves. Another example is the apple sawfly which has white maggots which bore into the fruit, the apples having scars on them and dropping prematurely. Insecticides (approved for edible crops) may be used.


Means "growing on rocks" in Latin.


Refers to plants which naturally grow on or around rocks.


A name given to a number of fungal diseases which cause a scaly and blistering appearance on the fruit or tubers of food crops. An example is scab occurring on apples and pears which affects the young shoots, leaves and fruit. Another example is the potato scab fungus which is soil-borne particularly in alkaline soils, which gives a "scabby" appearance to the tubers and reduces the yield of the crop.


Means "rough" in Latin.

scab of cucurbits

A fungal disease which attacks fruits, leaves and stems, causing sunken necrotic spots with gummosis. A fungus coating covers the spots in wet conditions.


Rough to the touch.


Means "ladder-like" in Latin.


Scalding or scorching may be a disorder of greenhouse and house plants where rapid variations in temperature, ventilation, humidity and fumes from heaters etc may damage the plants. Scalded plants may have leaves where the margins go brown and wither, brown or white spots appear evenly over the leaf surface plus young shoots and fruits may brown and wither. Provided scalded plants are placed in a better environment they may recover. Outdoor plants may be scalded by exposure to a harsh sun where for example grapes shrivel on scalded grapevines. Sun scorch can often be prevented by shading; possibly by using shade netting.


Any thin, dry flap of tissue; usually a modified or degenerate leaf.

scale insect

Refers to a number of insect species which use an outer scale to protect themselves during part of their life cycle, where they are attached to the plant. They may suck sap from the shoots and foliage. Small infestations may be removed by hand, but control may be done by an appropriate systemic insecticide. A tar oil winter wash may be given to fruit trees to give some protection against scale insects.


Bearing blunt or rounded serrations or teeth.


Scrambling; leaning on something for support, but not self-clinging.


Refers to a flower stem that arise from ground level and which bear no leaves, such as Amaryllis or Daffodil.


Refers to the practise of scraping the coating (testa) of a seed in order to aid water uptake and germination. Scarification may also refer to the raking over of a seedbed to break up the soil into small particles, or the raking over of a lawn to remove the thatch of grass clippings, moss, dead leaves etc and to allow better water penetration.


Thin, dry and membranous.


Means "noxious - wicked" in Latin.

scent glands

Glands in some flowers which help to produce a fragrance to attract insects to the flowers for pollination.


A fruit that breaks into 1-seeded portions or mericarps such as those in the families Geraniaceae and Malvaceae.

sciarid fly

They may also be called fungus gnats or peat flies (and include the larvae of small winged insects) which live in moist peaty soils and feed on the roots and stems of young plants. Control is generally by an appropriate insecticide.

scientific naming system

Refers to the binomial scientific naming system for species where the genus name and the species name together form a two part name such as "Primula vulgaris" (whereas the common name would be the Primrose). Similar species are grouped into a genus. Similar genera are grouped into a family. Similar families are grouped into an order. Similar orders are grouped into a class. Similar classes are grouped into a division. The plant divisions are grouped into the plant kingdom.


A shoot of a plant joined by grafting to the rootstock of another. Used to propagate trees and shrubs mainly, and where plants will not come true from seed, have naturally poor roots or are difficult to propagate from cuttings. Example uses are in fruit tree propagation where for example the scion wood of a vigorous apple is kept in check by the dwarfing characteristics of a particular rootstock.


A strengthening tissue composed of fibres or stone cells.


In the Mediterranean region and parts of the southern hemisphere such as in Australia, the trees are mostly evergreen and adapted to withstanding periods of drought and bush fires, referred to as sclerophilous vegetation. Trees such as olives, acacias and eucalyptus form a woodland able to grow on often sandy, fragile soils.


Refers to the hardening of the walls of cells, for example where stem tissues become woody.


Affected tissues become discoloured, brown and wet as they rot. A white fluffy fungal growth is often present at large and hard dark fungal bodies are embedded. These fall into soil and overwinter. Dahlias, delphiniums, gypsophila, sunflowers and lupins can be affected.


Means "broom-like" in Latin.


Another term for scalding. Scorching is a disorder which may be caused by hot sun, cold winds, or damage by chemicals, sprays or excess fertilizer.


Means "Scottish" in Latin.


A plant sprawling over other plants, fences etc.


This can refer to a deep layer of stone chippings which have been mixed with some loam, providing a freely-draining growing medium for plants that dislike water at their base.


Means "marked with lines" in Latin.


Any plant community dominated by shrubs. Also referred to as thicket.


Refers to plant parts which are covered in flaky-powdery scales.


A long handled tool with a curved sharp blade that is used in a sweeping action to cut grass, undergrowth or crops. This tool is not often used now since it can be dangerous, and requires some skill and effort. The job is often done now by powered tools.


A general term for plants growing in the sea. Rotted seaweed may be used as a fertilizer which is rich in potash.


A scissors-like tool mainly used for pruning. It is wise to clean and sterilise the secateurs between use on different plants to minimise the chance of transferring viral, bacterial or fungal diseases from infected plants to healthy plants.


The seed is an embryonic plant usually encased in a seed coat or testa. It is the product of the ovule after fertilization by the pollen grain; containing the embryo, food reserves and protective coverings. Individual seeds can have various sizes and shapes, and may be extremely small such as that of mustard and cress. The seeds may often be enclosed in a fruit, such as the pips in an apple.

seed beetle

In early summer beetles eat seeds on the outside of strawberries damaging the flesh. Can be found under stones or debris.

seed compost

Refers to any soil or compost which has been prepared for seed growing. Seed and cutting composts usually are moisture-retentive but free-draining and have low nutrient levels to avoid scorching the fine young roots. The rooted plantlets need growing on otherwise they will become straggly and weak.

seed-corn maggot

Larvae which attack sprouting seeds.

seed head

General term for the cluster of seeds.


Refers either to the process of producing seeds, or possibly the act of sowing seed.

seed leaf

A cotyledon that emerges from a germinating seed, and starts to photosynthesize to produce energy for further growth when true leaves will develop.


A young plant that has been raised from seed.

seed pod

An ovary containing seeds.


One of the parts of a cut or partially divided leaf, corolla or calyx.

seiridium canker

Cypress, junipers, leyland and thuyas foliage loses colour and lustre, later turns brown and dies. Tiny fungal bodies enter through fine cracks and notches causing the problem.

selective weedkiller

Refers to a herbicide that affects only certain types of plants such as broad-leaved weeds on a lawn.


Refers to a climber or other plant that supports itself by attaching itself to another plant, wall or other object. An example is Virginia creeper that uses suckering pads.


Able to self-fertilize.


The situation where pollen is transferred onto the stigma of the same flower, thus resulting in the plant fertilizing itself.


Not able to self-fertilize.


This refers to pollination where the pollen and the fertilized ovule has come from the same flower.

self seed

Producing seeds around the parent plant.


Refers to a plant that cannot pollinate itself, and so needs a partner plant for fertilization. It is important therefore that with crops such as apples, pears and cherries suitable pollinators need to be planted with self-sterile varieties.

semi ...

This is a prefix to a word which generally means "half" or "partly".


A plant that will shed some or all of its leaves in a cold winter or in a cold climate. Sometimes such a plant may be referred to as semi-evergreen.

semi-double flower form

A flower with more than 6 petals, usually in 2 rows.


Normally evergreen, but losing some or all of its leaves if a cold winter, or if growing in a cold area. Sometimes such a plant may be referred to as semi-deciduous.

semi-ripe cutting

A portion of a plant that is removed and used for vegetative propagation: semi-ripe cuttings are taken from half-ripened wood during the growing season.


Means "ever-flowering" in Latin.


Means "grey-haired" in Latin.


Means "sensitive" in Latin.


One of the outer set of usually green organs surrounding the flower bud and protecting it before the bud opens. The sepals collectively form the calyx; they may sometimes be brightly coloured and petal-like. In some flowers the petals may be replaced by sepals, such as in anemones and clematis.


Means "resembling a sepal".


A division in the ovary.


Bearing serrations or saw-toothed.


Means "edged with teeth" in Latin.


Minutely serrate, with small saw-like teeth.


Lacking a petiole or stalk.


Means "without a stalk" in Latin.


A term that may refer to the "setting" of blossom which has been pollinated and is now developing into seed or fruit. A "set" may also refer to onions, shallots or potatoes that are used for planting.


Covered with bristles.


Means "bristled" in Latin.


Reproduction involving the fusion of male and female gametes.


Although all photosynthesising plants need light, many plants have naturally adapted to shady conditions and will not thrive (possibly suffering scalding or sun scorch) in full sun. Many ferns for example are usually woodland or forest plants. Plants needing full sun which are positioned in shade will generally become weak and leggy, possibly becoming unable to flower and even die.

shade netting

Refers to any form of shading by a net or by other means to reduce the light level and direct heat experienced by the plant (avoiding scalding or sun scorch). This can also cut down on the transpiration requirements of the plant and enable the growing of plants in hotter, more arid climates than would otherwise be possible.


This disorder may be found in grapes where the fruit stems wither and the grapes dry up. This may be caused by waterlogging or other poor soil conditions.

shanking of grapes

Individual berries within bunch fail to colour normally. They become wrinkled and taste bad if eaten.


A more or less tubular structure surrounding another; as in the lower part of the leaves of grasses.

shelter belt

This may be another name for a windbreak, or it can refer to a large geographical area that is protected from the prevailing climate by mountains or other features.


Some prey on other insects and some suck sap of hawthorn, birch and various other plants. Several species are common including the common green shieldbug (Palomena prasina). On balance they do not cause much of a problem.


The leafy part of a plant, usually aerial.

short-day plants

Refers to plants that may be triggered into flower by long periods of dark, such as chrysanthemums.

shot hole

A disorder in the cherry and plum trees where the leaves are full of small holes. (If gum is oozing from the bark this may be bacterial canker.)

shot hole borers

Tunnels and small holes are made where grubs feed through. Gum exudes from the holes. The beetles responsible usually attack already weakened trees, in severe cases the tree may die. Plums, cherries, almonds, apples and pears can be affected.

shot-hole disease

Refers to leaves which seem to have had small holes punched out of them. This may be caused by a bacterial canker (such as in plums and cherries), or a fungal disease (such as in peaches).


Similar tool to a spade, but a shovel has rounded sides to handle loose or semi-liquid material.


A woody plant with no distinct trunk, the main branches arising near ground level. There may be little distinction between large shrubs and small trees, and some shrubs such as rhododendrons can form quite large trees.


A term for an area mainly planted with shrub-sized plants.


A tool with a curved sharp blade attached to a short handle, and is used in a sweeping action to cut grass, undergrowth or small branches etc. This tool should be used by adults with care, and for safety a hooked stick can be used in the other hand to pull debris out of the way.

side bud

Another term for a lateral bud.

side dressing

Refers to an application of a mulch or fertilizer which is applied along a row of plants without touching the plants themselves.

side shoot

Generally refers to any lateral growth from the stem.


Meaning "in the shape of a S".


Means "well-marked" in Latin.


Grass and other green vegetation kept compressed and under cover to exclude air in order to prevent excessive decomposition, and used for winter feeding to animals.


Soil or rock containing silica, and in consequence giving rise to acid soil. For example, sandstones are rich in silica (or quartz) and are siliceous.


Having a covering of soft fine hairs.


A soil formed by a river or other water depositing eroded material. The particles are finer than sand but coarser than clay, and so is generally free-draining and is usually very fertile.

Silurian period

A period of time in the Earth's development 400 to 440 million years ago. The oldest true land plants such as "Cooksonia" appeared, which had a simple branching structure. Aquatic animal life noticeable in the fossil record; lamellibranchs become abundant.


Means "of woods" in Latin.

silver fir adelgid

Smaller stems develop lumpy growths caused by a sap-feeding insect.

silver leaf

A fungal disease that infects plums and other fruit trees including apricots, peaches, cherries, apples. The fungus enters the wood usually through a wound, and can eventually spread to the whole tree. Leaves become silvery in appearance, and infected branches should be removed and wounds painted with a sealant.


Means "wood-dwelling" in Latin.


This is a residual herbicide and so stays in the soil. In heavy doses it will inhibit the growth of all plants. It may be used to keep paths and drives clear of weeds for long periods, or in smaller doses it may be used selectively to prevent growth of weeds in rose beds or orchards etc.


Refers to leaves or other organs that are not divided.

simple leaf

An ordinary single leaf.


Means "of China" in Latin.

single digging

Single digging means cultivation to one spade depth, whereas double or trench digging means cultivation to two spade depths where soil is heaped up in two stages.

single flower form

A flower with one row of usually 4-6 petals (having its normal complement of petals).


Means "unusual" in Latin.


Strongly waved, such as in a leaf margin.


Means "with a waved edge" in Latin.


The cleft or recess between two lobes.


A term describing an organism growing in a tube-like form.


The name for the sap-sucking mouthparts of insects such as aphids.

slime flux and wetwood

Watery, malodorous substances coloured orange, pink or white 'ooze', from stems of affected plants.

slime mould

Yellow or orange growth develops on stems as a result of various species of slime mould. Slime moulds are classified in the Protista kingdom, and are an aggregation of simple one celled organisms, that are notable for their ability to move as if they formed a single organism.

slitting a lawn

The process of cutting slits in the turf to improve aeration and encourage the growth of lateral shoots.

slugs and snails

These feed on decaying or living plant tissue, and are generally considered pests by the grower since they may attack seedlings, leaves, fruit and most soft parts of a plant. They are mainly active at night (nocturnal) especially in mild, damp weather. They may hide under stones and in debris during the day, and so keeping the area clear of these reduces the numbers. There are several control methods including traps, hand picking at night, chemical pellets and biological control.


Slugworm is the name given to sawfly larvae, since they resemble small slugs but can be seen to have legs. They are pests of roses, pears and cherries, eating the leaves, and may be controlled by an appropriate (approved for edible crops) insecticide.

small ermine moths

Stems and foliage of hawthorn, blackthorn, bird cherry, willow, apple, euonymus and sedum can become covered with dense, whiteish silk webbing in summer.

smallest flowers

The floating flowering plant called Australian Duckweed (Wolffia angusta) is 0.3 mm wide and 0.6 mm long.

smallest seeds

Seeds from some epiphytic orchids are so small that 992 million seeds would be required to weigh 1 gramme.

smoking treatments

In greenhouses insecticides and fungicides may be applied with "smokes" where the fumes diffuse around the enclosed area. These should be used with great care, since the fumes are likely to be toxic.


A fungal disease affecting Narcissus where the stored bulbs rot. The growing leaves are spotted and rotten in wet springs; black resting bodies on bulb.


This is a fungal disease that can affect onions, where the leaves appear to have soot-like growths on them.


This is one source of water for many terrestrial plants, and snow can have an affect in the light available to plants. Depending in the 'type of snow' the plants may be either insulated from the lowest temperatures, or if the snow is compacted and icy the plants will be subject to low temperature stress. Unless the soil is covered over a prolonged period, or other factors such as permafrost apply, then it is the temperature that is the predominant factor in assessing the hardiness required by a plant.

snowdrop grey mould

Foliage and stems develop a grey mould and the plant begins to rot.


Refers to a pit filled with rubble, which allows water to accumulate and gradually percolate into the soil.


Refers to plants that form clumps or masses of suckers from beneath the ground.


An element (symbol Na) which is a micronutrient, needed by plants but only in small quantities. Sodium is usually present in soil but if deficient then susceptible plants may suffer wilting, chlorosis and random necrosis of the leaves. To correct a sodium deficiency, manure or a balanced fertilizer can be used which contains proportions of nitrogen, phosphorus and potassium (NPK) plus other minor nutrients.

sodium chlorate

This is a total herbicide which is translocated in the plant and also stays in the soil. It is useful for clearing waste land and for keeping paths, drives etc clear of weeds but it has important drawbacks since it may easily be carried to places in the soil where it was not wanted.

sodium molybdate

This chemical is sometimes used diluted in water as an insecticide.

sodium nitrate

This is a chemical fertilizer which supplies nitrogen. It is fast-acting and may be effectively used in spring and summer, although care is needed to avoid scorching plant leaves. Also known as nitrate of soda or nitratine.

sodium tetraborate

An active ingredient of some pesticides and ant traps.

soft fruit

A general term for fruits such as raspberries, currants and gooseberries which grow as "bush fruit", and do not have hard stones (which contain seeds) in the fruits.

soft rot

A bacterial disease that can affect the roots and stems of crops such as cabbages, celery, onions, root crops and some ornamentals. The tissues become wet and slimy, and rapidly spreads to destroy the plant. The bacterial infection generally results from physical damage during cultivation or handling, and is exacerbated by poor ventilation.

soft scale

Flat pale yellow-brown oval scales (up to 4mm) found on stems and undersides of leaves of both indoor and outdoor plants. Large amounts of honeydew are produced and sooty moulds may develop.

soft soap

This has some insecticidal properties and is occasionally used to control aphids and red spider mite. Insecticidal soaps may be used against a wide range of insects, but can also harm beneficial insects.

softwood cutting

A portion of a plant that is removed and used for vegetative propagation: softwood cuttings are young growth taken at the beginning of the growing season. Generally softwood cuttings need to be kept warm and moist until they have rooted.


Generally refers to the plant growing medium, but more specifically to the natural covering of the rocks. Soils may be classified in a number of ways such as the following: Light, medium or heavy according to the proportion of clay content. Fragile soil refers to those prone to soil erosion. Acid, neutral or alkaline soils are graded according to their pH reading. Terms such as loamy, chalky, sandy may be used. The "Avery soil classification system" and other systems may also be used. Generally free-draining but moisture-retentive soils are desired by most growers.


Refers to a disease or pest which continues living in the soil and which can then affect plants which are then planted in that soil. An example is the potato scab fungus which is soil-borne particularly in alkaline soils, which gives a "scabby" appearance to the tubers and reduces the yield of the crop.

soil capacity

Refers to the amount of water that a soil can absorb without becoming waterlogged.

soil conditioner

Refers to any material that is mixed into the soil to improve its structure, enabling it to become more moisture-retentive yet free-draining. Bulky organic manures are often used for this purpose.

soil erosion

This is one of the biggest dangers facing mankind. Soil is lost by many means including being washed or blown away in addition to being covered in concrete. It is important to protect soil from erosion since it is a valuable resource allowing plants to grow which supply ultimately all food (primary producers) and most other materials used by an expanding human population. Soil will take hundreds or thousands of years to regenerate. Much of the planet's land surface has been denuded of topsoil through human activity, and much natural topsoil is thin and fragile (fragile soil) such as that covering much of Australia.

soil heating

Under-soil heating may be used to help raise plants such as early lettuces. The heating may be done via hot water pipes, electric cables or even by rotting manure.

soil-less cultivation

Another term for hydroponics.

soil mark

Refers to the level at which the plant was growing in the soil before it was transplanted.

soil moisture deficit

Refers to the amount of water needed to bring a soil back to its soil capacity.

soil; raised level

If soil level is raised around existing plants, the roots can be killed by being deprived of oxygen. Foliage and stems subsequently deteriorate and bark may also be injured.

soil solution

Refers to the water in the pores of the soil, which has dissolved in it various nutrients and other chemicals including oxygen. Plants absorb nutrients and oxygen from the soil solution via the root hairs on the roots.

soil testing and analysis

Growers need to be aware of the pH reading and nutrient levels of the soil they are cultivating. Soil testing usually refers to a limited investigation of these values, whereas soil analysis usually means that a comprehensive chemical investigation is done by a laboratory. There are soil testing kits available that give a reasonable indication of the pH and the NPK values (nitrogen, phosphorus, potassium) if used correctly.


Means "solid - not hollow" in Latin.

Solomon's seal sawfly

Foliage is eaten right down to stems. Leaves are ragged or eaten to veins. In summer the white caterpillars move into the soil where they overwinter. The adults emerge in spring the following year and lay eggs in the stem where a purple scar may develop.


Means "sleep inducing" in Latin.

sooty mould

This is a black powdery fungal mould which occurs on the leaves and stems of some plants, usually because the mould is growing on honeydew which has been excreted from sap-sucking insect pests.


A group of sporangia on plants in the Pteridophyta division.

sour soil

May refer to soils that have become more acid, possibly because of poor drainage. Improving the soil structure and applying lime can counter the acidity.

sowing seed

The act of scattering or planting seed (drilling) for propagation. Sowing seeds on an agricultural scale is usually done by a mechanical drill. On a garden or horticultural scale, straight furrows in the soil may be created by using a stick or a spade. If scattering seed (possibly for a lawn) then a consistent coverage needs to be attempted by marking out the ground and using appropriate weights of seed.


A tool used for digging and general cultivation purposes; there are many designs available.


A fleshy spike bearing flowers and often ending in a swollen club-like apex (as in the genus Arum).


Means "scattered" in Latin.


A large bract (or sometimes 2) enclosing a flower head (as in the genus Arum).


Means "spatula-like" in Latin.


Spoon or paddle-shaped; broader towards the apex and narrowed to the base.


A term that refers to the way fungi or some plants propagate themselves, where many small shoots spread out from the parent plant.


A group of individuals having similar characteristics, and which interbreed. Similar species are grouped together into a genus. The species (or specific name) is the second part of the Latin name or binomial scientific name. There is a botanical convention for nomenclature that the species name is in lower case and that the binomial name is printed in italics. Species may be abbreviated to spp.

specimen plant

Refers to a single plant grown for display, often so that it can be admired from all sides.


Means "showy" in Latin.


Another name for an antherozoid.


A seed plant ie. an angiosperm or a gymnosperm.


Another name for an antherozoid.


A type of moss which is lush and moisture-retentive, making it useful as a constituent of growing media, and for orchid culture. Also used for techniques such as air-layering and for displays such as hanging baskets.


Flowers borne in spikes.


Means "spike-like" in Latin.


An arthropod (animal with an exoskeleton) with 2 main parts to the body and 4 pairs of legs.


A simple, unbranched inflorescence of stalkless flowers.


A secondary spike or part of a compound spike. Also in grasses a group of one or more flowers sub-tended by two sterile bracts or glumes.


A cultivation method for root crops grown on poor soils, where deep cone-shaped holes are made with an iron bar. The holes are filled with good soil and the seedlings grow in these specially prepared locations.

spinach blight

Viral disease of spinach where the leaves roll inwards and turn yellowish.


Means "spiny" in Latin.


Means "twisted" in Latin.


A spade depth; about 25-30cms or 10-12 inches.

spittle bug

Another name for a froghopper.

splice graft

A way of grafting the scion onto the rootstock where diagonal cuts through the stems are bound together.

split fruit

A disorder of tomatoes where the fruits split open when ripe


Fruits and stems are distorted. May show cracking, spiralling and twisting - usually running longitudinally and in the roots. Brown rot may then affect the split fruits entering via lesions. Growth may be stunted but the tree appears to be healthy. Other pathogens enter easily through the splits so dieback may occur.


Organs on the diploid sporophyte which produce haploid spores (on ferns and other members of the divisions Pteridophyta and Bryophyta). In heterosporous plants there are male microsporangia and female megasporangia.


A single reproductive haploid cell in plants in bryophytes, ferns and other pteridophytes. The spores are formed after meiosis in the sporangia of the diploid sporophyte generation. The haploid spores germinate to give the gametophyte generation. (Fungi also produce reproductive "spores", but they are not part of the plant kingdom.)


The (normally) diploid generation, producing haploid spores which germinate to give the gametophyte generation in bryophytes, ferns and other pteridophytes.


Horticulturists may refer to mutant plants as 'sports', and plant breeders can exploit these natural occurrences and cultivate them to create new plant varieties.

spot treatment

Refers to any treatment done on individual plants (such as applying weedkiller to weeds), where a wide-scale treatment is not desirable or possible.


A name for a disorder found in potatoes where dark streaks occur in the tubers. This may be caused by variations in the water content of the soil; improved drainage and cultivation may reduce the incidence.


Sprays may be applied to the plant for a number of reasons. Foliar feeds may be applied or just water to counteract the symptoms of wilting. Insecticides and fungicides may be applied with sprays, taking care to avoid drifting sprays. When spraying choose a non-windy day and take other precautions reading the instructions carefully. In general the finer the droplets, the better the coverage, and there are many spraying devices available from hand-pumps to large-scale agricultural spraying systems.


Refers often to a machine for "muck spreading" where rotted manure is distributed over the land by a powered machine. However, it is a general term for any type of equipment for spreading fertilizer or other substances.


Standing outwards or horizontally.


A general name for a small twig, branch or shoot.


A small insect able to jump using its forked tail which is usually folded under its body. It feeds on dead and living plant tissue and is regarded as a pest by the grower, and may be control by an appropriate insecticide.


Usually refers to water sprinklers which can use large amounts of mains water over some period for the irrigation of lawns and gardens.

sprouts; blown

Instead of tight sprouts they are open and leafy.


A hollow, more or less cylindrical projection from a petal or sepal; it usually contains nectar such as in the flowers of columbine (Aquilegia). It also refers to a small branch on a fruit tree that carries fruit such as apples or pears; if the spurs get too large over the years with too many buds the fruit size becomes reduced and so pruning may be done during winter.

spur bearer

Refers to a fruit tree that produces its fruit on spurs such as apples and pears. (Tip bearing fruit trees carry the fruit buds at the end of the shoot of the previous season's growth.)

spur blight

A disease affecting raspberry and loganberry where purplish areas develop around buds; buds fail to grow or soon wilt.

spur pruning

The cutting back of the side shoots to within 2-3 buds of the main shoot to encourage fruiting spurs to form. Also referred to as spurring back.

spurring back

Also known as spur pruning.


Means "untidy" in Latin.


Means "scaly" in Latin.

square cms

A measure of area equivalent to 0.155 square inches.

square foot

A measure of area equivalent to 0.093 square metre.

square metre

A measure of area equivalent to 10,000 square cms or 10.76 square feet or 1.196 square yards.

square yard

A measure of area equivalent to 9 square feet or 0.836 square metre.


Squirrels can be very destructive. They dig up and eat crocus corms, tulip bulbs, flower buds and shoot tips. They take nuts and tree fruits and can strip the bark from trees. Newly planted bulbs are more at risk and are often eaten in the autumn and winter. Gardens in rural locations are more vulnerable to squirrel attacks.

Stachys case-bearing caterpillar

In early summer the foliage develops brown blotches where the internal tissue has been eaten out.


Refers to a tree which has some dead branches projecting above the living tree canopy.


A support for plants; from a cane for Delphiniums to a heavy wooden stake for a young tree. Plants may need support when cultivated after transplanting or because they are being grown in an unnatural environment, for example specimen plants are exposed in a way they may not be naturally as they would be surrounded by other plants.


A general term for a petiole (a leaf-stalk), a pedicel (a flower stalk) or sometimes a stem (the main plant axis producing buds, leaves etc).


One of the male reproductive organs of the flower which bears the pollen. The stamen is composed of the filament which holds the anther which produces the pollen grains. The pollen is to be transferred by a pollinator such as wind, insects etc to the female ovule during the process of pollination.


An infertile or rudimentary stamen without pollen. Some staminodes resemble petals; as in some peonies, and in other flowers with fully double flower forms and double flower forms.


May refer to a group of trees or other plants growing on their own.


The broad upper petal of a flower of the pea family. Also the inner petals of an iris which stands erect. Also referring to the upright shape of plants, such as "standard fuschias" or "standard roses" with a clear length (about 1 metre or so) of bare stem below the first branches. 'Half-standard' is a term that may be used to refer to plants with a shorter length of bare stem.


This is a polysaccharide (composed of many sugar molecules) compound derived from glucose and other sugars during the plants metabolism. Starch is generally used as a storage compound by plants and forms the basis of flour from the endosperm of grasses such as wheat. It is also a main component in tubers such as potatoes and other storage organs.


Refers to the process of stimulating dormant plants to grow. Usually this means supplying moisture, warmth and light.


This may refer to the process of soaking seeds with a hard coating prior to sowing, since the soil moisture may not be sufficient. This can also refer to the making of a liquid manure by suspending a bag containing animal manure in a container of water; the resulting liquid can be used as a liquid feed onto the soil.


The central vascular tissue of a root or stem.


Means "star-shaped" and may refer to the flower (such as Magnolia stellata) or may refer to the overall shape of the branches and foliage.

stellatus or stellata

Means "star-like" in Latin.


The main ascending axis of the plant, which (in angiosperms) produces the leaves, flowers and axillary buds.

stem and bulb eelworm

A pest of Narcissus where the leaves are distorted and yellow mottled. There is a lack of flowers and brown rings are found within bulbs.

stem cuttings

A portion of a plant that is removed and used for vegetative propagation: stem cuttings is a general term for greenwood, hardwood, semi-ripe or softwood cuttings.


Leaves which are borne on the stem as opposed to basally.

stem nematode

This pest damages above-ground parts of plants and retards growth, the leaves are curled and the margins bent downwards.


Refers to the habit of some plants to produce roots above the ground level.

stem rot

Can be a general term for any disease (such as sclerotina rot) that affects the plant stem.

stem tuber

A swollen part of a stem such as the perennial underground swollen stem in cyclamens. The tuber is a storage organ where the food reserves are mainly in the form of starch.


A tree-less landscape. A type of vegetation consisting of grasses, and other herbaceous plants but no shrubs. (In the Mediterranean region this may develop with excessive grazing, absence of soil cover and low rainfall.)


Lacking functional sex organs and therefore infertile. It may also refer to soil or other substances which have been treated to kill fungal spores, bacteria etc.


Means "barren" in Latin.

sterilization of soil

A treatment given to soil or other growing media to destroy insects, fungal spores, weed seeds etc. Methods of sterilization include steam, heat and chemical treatments.

sterilization of soil by heat

The soil can be sterilised by raising its temperature in a number of possible ways, including baking for small quantities of soil or steam sterilisation for larger quantities. Soil that has been "sterilised" will be less fertile for a few months and so the addition of some compost (such as John Innes) will help.


The part of the female organ (pistil) which receives the male pollen grain. Normally situated at the top of the style, it is often covered with a sticky secretion to help catch the pollen.

stilt roots

Refers to adventitious roots that arise from branches and grow down to support the plant. Examples are the stilt roots of mangroves and some other plants growing in sub-tropical and tropical coastal regions.


A small sheath enveloping the growing point, often retained on the twig opposite the petiole base (often paired), leaving a scar when it falls off.


In horticulture the term stock can refer to the rootstock which provides the root system on the stem of which another kind of plant is grafted. Fruit trees may be grafted onto a less vigorous rootstock to limit the size of the tree. Some scions are grafted onto rootstock which are resistant to root diseases and are more vigorous so providing a strong root system. All shoots should be removed from the rootstock otherwise suckers may arise and over-run the more desirable grafted variety. Botanically the term stock can also refer to a short erect underground stem bearing roots. The term stock can also refer to plants kept for vegetative propagation purposes


A short shoot which develops a new plant at the tip, eventually severing connection with the parent plant. A 'stolon' is similar to, but different from a 'runner' which forms new plants at the nodes of the stem.


A pore (small hole) in the epithelium (especially of the leaves) which allows gaseous exchange and transpiration by the plant. The opening and closing of the stomatal opening is controlled by guard cells which alter their shape by adjusting their turgidity.


A measure of weight (st) which is equivalent to 14 pound (lb) or 6.35 kilogram. The term "stone" can also refer to the pyrene which encloses the seeds in many fruits of the Prunus family, including plums, cherries, peaches, apricots and nectarines.

stone cells

Heavily lignified (impregnated with lignin) cells produced by the plant where extra strength is required.


Can refer to an old plant that is being used to supply propagative material. Such plants may be part of a horticulturist's stock.


The act of removing the growing points of a plant to restrict growth.


Another term for pinching out.

storage organ

Refers to any organ which is used to build up food and water reserves by a plant, for a time when growth is needed or drought occurs etc. Examples of these are tubers, bulbs, corms, rhizomes or the above ground fleshy stems of succulents and some cacti.

storage rot

A general term for diseases that affect stored fruit and vegetables, and includes the affects of soft rot, stem rot etc. Often this is can result from physical damage during cultivation or handling, and is exacerbated by poor ventilation.


A "mating group" within a species (or a variety within a species) with distinctive physiological or morphological features (especially with regard to fungi, bacteria or viruses). A certain seed may be described as being from a certain "strain" meaning that it has some noticeable differences from other strains; if the differences are more marked then the plants may be described as a certain form.


Means "straw-coloured" in Latin.


This describes leaves or other organs that are long and thin with parallel sides for the most part.


Can refer to the layers of different types of soil or rock which are observed when seen in cross-section. It can also be another term for stratify.


Breaking the dormancy of certain seeds by leaving them in the cold for a period. The seeds can be placed between layers of sand in trays which are left outdoors in winter, and then retrieved for sowing in the spring. This may be done to the seeds of some trees and shrubs.


The dried stalks of wheat, barley or other grain crops which may be used for animal bedding. Straw may also be rotted down and mixed with soil as a soil conditioner. Fresh straw may be used as a mulch to and to protect strawberries from becoming damp or muddy which can lead to a rotting infection.

strawberry beetle

A pest of strawberries which lays its eggs in the flower bud and chews its stem. The larvae develop in the flower buds which later drop.

strawberry black eye

Flowers develop a dark brown or black centre. The flowers damaged don't form fruit.

strawberry green petal

Flowers are reduced in size and bear green petals. Fruit produced, if any, are very small and distorted.

strawberry grey mould

The fruits start to develop normally, but then brown/black necrotic patches develop. The fruits deteriorate with fuzzy fungal growth over the surface.

strawberry leaf spot

Red-purple spots develop on leaves and off-white fungal growths develop on the spots. It may spread to flowers and stems.

strawberry mildew

Fungal disease of strawberries which causes purple blotches above and white beneath the fruit.

strawberry mite

A pest of strawberries where the larvae and adults damage the leaves and inflorescences. The leaves turn olive-green, young leaves are stunted, and some of them turn brown.

strawberry nematode

A pest of strawberries where delayed growth is caused and a small number of fruit set.

strawberry pot

A container which is designed with many holes to grow strawberries, or possibly other plants. Such containers may be stacked in a tall cylindrical structure to make the most use of the space available.

strawberry red core

Groups of stunted plants appear in late spring bearing red-brown, stiff leaves.

strawberry seed beetles

Seeds are removed from surfaces of fruits causing small, dried-up brown patches.

strawberry viruses

Stunting and distorting of whole plant and yellow discolouring.

strawberry yellows

Leaves turn yellow and the entire plant may appear to be yellow.


Refers to various viral diseases whose symptoms are streaks or spots of brownish black on the leaves, flowers, fruits and stems of infected plants such as tomatoes and sweet peas. The viruses can be spread by aphids or other sap-sucking insects, or possibly on secateurs used for pruning.


Refers to the difficulties a plant may face in the environment, such as drought conditions (water stress) or lack of nutrients in the soil.


Having fine, longitudinal hairs, or it can refer to any longitudinal pattern.


Means "finely-streaked" in Latin.


Means "very straight - erect" in Latin.


A name given to a cluster of fruit, such as that found on blackcurrants. The pulling off of such clusters of fruit may be referred to as "strigging".


Covered with flattened, fine, bristle-like hairs.

striking a cutting

Refers to the act of rooting a cutting.


Another name for a trimmer.

strip cropping

Refers to the harvesting of the whole crop in one go, which is usually done with crops arranged in rows.


A name for an angiosperm cone-like fruit such as "hops" (produced by Humulus lupulus).


Refers to the slowing up and reduction in size of a growing plant. A plant can be stunted for a variety of reasons such as a deficiency of nutrients, light, water, exposure to extreme winds, temperatures or damage from chemicals etc. It may be also that a particular plant individual has a genetic modification or mutation.


A more or less elongated projection of the ovary which bears the stigma (in angiosperms).


Means "with a prominent style" in Latin.


Means "agreeable" in Latin.


Refers to plants which originates from the lower slopes of the alpine regions. Such plants will probably grow on higher slopes, but also grows below the tree line.


An impervious waxy substance with which cork and other cells are impregnated.


Means "corky" in Latin.


Referring to a perennial plant that is woody at the base, but not so extended as a shrub, with the aerial herbaceous shoots dying back in winter.


This is the soil layer beneath the topsoil, and during most cultivation it is usually not disturbed, although double digging and other methods may affect it depending on the depth of the topsoil. Only larger plants, trees and shrubs have roots that penetrate down into the sub-soil. The sub-soil may differ geographically depending on the underlying rock. Clay sub-soils will retain more water in the topsoil than an aggregate sub-soil.


A group of individuals within a species which have some distinctive characteristics, and often a well marked geographical range. The characteristics separating subspecies are more marked than those separating varieties. There is a botanical convention on nomenclature that subspecies or variety or form names are in lower case if they are of natural origin, and printed with initial capital letters if they are human-made or cultivars. (Often the cultivar name is placed in quotes but in this package the cultivar names are not placed in quotes since they are distinguished by having initial capital letters.) Subspecies may be abbreviated to subsp.


Referring to a plant, seeding and establishing itself in the wild after being brought into a locality from elsewhere.


Refers to the growing medium for the plant, which may be the soil, tree surface etc.


To be below and close to. For example, a subtending bract which bears a flower in its axil.


Means "underground" in Latin.


Refers to the regions of the world bordering the tropics, approximately beyond latitudes 23 degrees north and south of the equator. Generally sub-tropical plants grow in quite hot conditions. They may be grown in temperate climates but they are usually susceptible to frost (tender), and need protection in winter.


Refers to leaves or other organs which are awl-shaped (broad based, long and tapering to a point).


Refers to a periodic sowing of vegetable and flower crops, to enable the harvesting over a long period as they periodically mature.


Any plant which stores water in the leaf, root or stem, so that it is fleshy, juicy or pulpy. Usually this is an adaptation so the plant can survive drought conditions eg cacti.


Means "juicy - soft" in Latin.


A shoot arising below ground from the root or rootstock (often at some distance from the main stem). These are often removed by growers since they can overwhelm the more desired scion variety.

suckering pads

Refers to pads of plant tissue that stick to walls or other surfaces, such as that used by the Virginia creeper.


This is a form of sugar (made up from glucose and fructose) which is produced by many plants such as sugar cane and beet. (It is the form of sugar that is used for putting in tea and coffee.)


Means "shrubby" in Latin.


These are carbohydrate compounds such as glucose, sucrose and fructose. They are produced in various proportions by plants as a course of their metabolism and for storage purposes. Honey is a sugary by-product of plants since the pollen and nectar is collected by bees for their own food storage.

sulphate of alumina

Another name for aluminium sulphate.

sulphate of ammonia

Another name for ammonium sulphate.

sulphate of copper

Another name for copper sulphate.

sulphate of iron

Another name for iron sulphate or ferrous sulphate. This is sometimes used as a moss killer and fertilizer on lawns. It can be used alone or in combination with other chemicals such as sulphate of ammonia, to make lawn sand.

sulphate of magnesium

Another name for magnesium sulphate and sometimes known as Epsom salts.

sulphate of potash

Another name for potassium sulphate.


This element (symbol S) is needed in significant amounts by plants for healthy growth. If deficient then the plant will suffer similar symptoms to a deficiency of nitrogen with a loss of green in the leaves and stunting. To correct a sulphur deficiency, manure or fertilizer containing sulphur such as potassium sulphate can be applied. A balanced fertilizer can also be used which contains proportions of nitrogen, phosphorus and potassium (NPK) plus other minor nutrients. If the yellow powder flowers of sulphur is added to the soil it will have an effect of increasing the acidity, and this technique may be used for this reason. Sulphur may also be used as a form of fungicide treatment.


Means "pale yellow" in Latin.

sulphur treatments

Sulphur can be used as a fungicide and is particularly useful against mildews and storage rots. It is available as a fine powder (flowers of sulphur) for use direct or in colloidal or wettable forms to be mixed with water and applied as a spray according to the manufacturer's instructions. It is also available as a smoke to control moles, rats and mice.

summer chafer

A name given to flying beetles which may be seen on summer evenings. The larvae and adult beetles feed on leaves and roots creating holes.

summer pruning

Refers generally to any pruning done in summer, done usually to check vigorous new growth. This pruning will divert more energy into flower buds and developing fruit.

sun scorch or scald

Plants may be scalded by exposure to a harsh sun where for example grapes shrivel on scalded grapevines. Scalding can often be prevented by shading; possibly by using shade netting.


Means "magnificent" in Latin.


Meaning above, such as a superior ovary where the calyx, corolla and stamens are inserted at the base of the ovary.

superphosphate of lime

This may be called calcium phosphate. It may be used as a base dressing before planting to provide the potassium nutrient. (It does not have a significant affect on the soil pH reading.)

support for plants

This can be provided in many ways. Examples are stake, pergola, trellis and tying-in plants to other structures or other plants. Self-clinging climbers such as Virginia creeper use walls, rock faces or tree trunks for support.


This is a term for a detergent substance that may be included in some insecticide and fertilizer sprays. The surfactant reduces the surface tension of the liquid so that it wets the plant surfaces more thoroughly.


Means "of Susa, Persia" in Latin.


Means "pendent" in Latin.


A name that may be used for any expanse of short grass.


Refers to the width of grass mown by a grass cutter.

sweetcorn smut

Individual kernels on the cob become swollen and deformed. Each goes pale grey and bursts to release large quantities of black powdery spores.

sweet soil

Refers to neutral soil or slightly alkaline soil ie not acid soil.

swelling bud

Refers to the bud which has started to enlarge after a dormant period. The swelling bud will go on to produce either leaves or flowers.

swift moths

Large soil living caterpillars feed on roots and damage bulbs, corms and rhizomes. The plants wilt.

sycamore sooty bark disease

Leaves wilt and die back on infected branches, green or yellow staining may be visible.


Means "of woods and forests" in Latin.


An association between two organisms in which there is mutual benefit. An example could be the mycorrhizal relationship between the roots of a plant and a fungus, where the fungus absorbs phosphates and nitrates from the soil and produces vitamins helpful to the plant, while the plant gives up sugar to the fungus. Another example is the association between nitrogen-fixing bacteria and the root nodules of legumes, where the bacteria receive nutrients from the plant and the plant gains additional nitrogen.


These arthropods resemble centipedes, but they have 14 body segments and 12 pairs of legs. They feed on roots and may be controlled by a suitable insecticides.

sympodial branching

The type of branching in which the terminal bud ceases to grow, growth being continued in each instance by the uppermost lateral branch.


Refers to any sign or appearance which indicates a weakness through a deficiency, infection by a disease, attack by pests or change resulting from a disorder.


Referring to leaves that appear alongside the flowers.


This is an alternative Latin name for the same plant. This may be a result of the plant being reclassified or from having been named by two different people in the first place.


Refers to the ability and process of biochemically constructing compounds eg plants can synthesize most vitamins themselves. It can also refer more generally to the manufacture of any compounds eg man-made fungicides may be described as synthetic fungicides.


Means "of Syria" in Latin.


Means "sleep inducing" in Latin.

systemic treatments

Sometimes referred to as translocated, it means that the entire bodily system is affected. For example, systemic pesticide is a chemical that works by being absorbed by the plant and being harmful to pests that feed on the plant sap or tissues. Systemic or translocated herbicides are absorbed into all the tissues of the target plants, and are often used to kill perennials. Care must be taken especially on food crops, the instructions being followed diligently.

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