This grower is fairly sure of this plant identification.
these are bulbs
collection from west derby
Iris, Flag iris, Fleur-de-Lys, Sword lily
Iris prismatica (Iris). A rhizomatous, beardless iris with thin, wide-spreading rhizomes which forms large clumps of grass-like leaves and grows up to 70cm long. It bears clusters of violet-blue flowers, veined blue on slender, angled stems, in early and mid summer.
They are fully hardy, but some groups may thrive only in specific growing conditions. All irises are best planted in late summer and early autumn. Outdoors you can grow them in well drained, fertile, neutral or slightly acid or alkaline soil in full sun to lightly dappled shade. In order for irises to thrive, most of them need long, hot summers. Irises that require protection from rain or frost should be grown under glass.
Grown for their distinctive and colourful flowers. Suitable for coastal conditions.
Italics = data drawn from parent genus or speciesView Full Plant Finder Record