It's mid December, we're all thinking about wrapping up the Christmas presents, but there's a wrapping job in the garden which needs to be done: yes, it's time to wrap up the vulnerable plants again.
In most of my gardens here in Oxfordshire, I am asked to wrap up plants in pots, and in some gardens, hydrangeas which are planted in the ground, but are not yet well-established.
We had a cold snap last week, which is typical for early December, and now it's gone mild again, which is also typical. But although these “semi-tender” plants survived that brief chilly period without harm, they won't be happy if it turns cold again, so I've make the most of these few mild days to get out there and wrap them all up.
If you have a lot of decorative terracotta pots, it may well be a good idea to wrap the pot, if not the plant: protecting the outside of the pot with a layer or two of bubble wrap will extend the life of the pot by reducing the risk of damage by frost, and has the additional benefit of giving the roots within it an extra layer of insulation.
Talking of roots, that's why we often find that plants in pots need more protection than the same plant would if it were planted in the ground: pots, being above the ground, will receive freezing air all the way round them, so the roots of the plants are only an inch or two away from the icy cold air, instead of being safely tucked several inches underground.
So here are a couple of quick tips for this annual chore:
Use horticultural fleece, old net curtains, or landscaping membrane to cover the plant, not any sort of plastic: plastic “sweats” in the sun, causing condensation on the inside which then goes mouldy, yuck!
Don't use cotton sheets if you can avoid it - they soak up the water as the frost melts (or when it rains) and become very heavy, which can then damage the plants. And wet conditions lead to mould - again, yuck!
My usual technique is to take a length of horticultural fleece, fold it in half to get a double thickness (or go around twice) then wrap it around the plant: hold it in place with clothes pegs while you arrange it in a satisfactory manner (which means ensuring the covering comes right down to the lip of the pot, and right up to the top of the plant), then tie around the base, the top, and half-way up. I often leave the pegs in place, if it's one of those shrubs with a lot of branches - pegs can help to keep the string from slipping off.
If you have a lot of delicate plants all in the same bed, you can either wrap them individually, or you can make a frame and cover the whole lot in one go - as per the first photo, above.
Sometimes a low-branching shrub such as Hydrangea or a youngish Fig can appear to be too wide to be wrapped, but you can often gently encourage the branches to curve upwards by tightening the ties a little at a time. Once it's well corseted, you can add another layer of fleece on top, for neatness, if you wish.
Make sure that you close over the top of the arrangement (last photo), otherwise it fills up with opportunistic bugs, using it as a cosy hotel for the winter! Folding over the top also encourages winter rain to run off, which reduces the dampness inside, and therefore reduces the risk of mould.
In early spring, I open up the tops of the wrappings to let in fresh air and the rain, but leave the outer wrappings in place for a couple more weeks until I'm pretty sure that the frost period is finished, at which point oh joy, all the wrappings can come off and be washed and stored away until the next winter.
The only problem with doing this year after year is that the plants get bigger and bigger, and you need larger pieces of fleece, as you can see from the photos of a single pot: that's the same Fig, getting bigger year by year!