Colchicum: Autumn Crocus
Height 15-20cm (6-8in)
Planting distance 15-23cm (6-9in)
Flowers early to late autumn
Sunny or partially shaded site
Corms available in mid and late summer
Colchicums are renowned for the lovely colours they introduce to the garden in autumn – muted lilacs, purples and pinks that seem to blend perfectly with fallen leaves covering the ground. An ideal site is among rough grass which supports the 15-20cm (6-8in) high leafless stems during flowering time and hides the mass of coarse, untidy leaves that develop in spring. All colchicums are hardy, so can be left undisturbed for years. Don’t confuse them with the genuine crocus.
Colchicum autumnale has lilac-pink goblet-shapedthat appear in early and mid autumn. The stems are particularly fragile so ideally this species should be grown among rough grass that can be left uncut in spring and autumn. Plant 10cm (4in) deep and 20cm (8in) apart. A double-flowered white form ‘Album-plenum’ and a single white form ‘Album’ are also available. Colchicum speciosum has flowers which are varying shades of mauve. They appear from early to late autumn. It is a more robust species with a stronger stem, so can be grown in a border, preferably a shrub border where the 40cm (16in) high leaves that appear in spring can’t smother other plants. Plant in a group of at least 10 corms in the dappled shade of a shrub or a small tree. Set them about 10cm (4in) deep and 15cm (6in) apart. Varieties include ‘Album’, a pure white form. Dutch hybrids have stronger coloured flowers, appearing between early and late autumn. They are more robust and easier to grow. Popular varieties include ‘The Giant’ (rosy-lilac), ‘ Wonder’ (lilac-rose), ‘Waterlily’ (mauve with double flowers) and ‘William Dykes’ (lilac-pink).
Colchicums grow in any soil provided it is well drained, but they are more likely to spread in fertile soil. A site in sun or partial shade is suitable. Plant in mid to late summer or as soon as they’re available, setting them in small clumps. Remove dead foliage.
Every third year, when the leaves die down in summer, dig up the corms and separate any small cormlets and replant them.
Pests and diseases
Slugs may eat the leaves and corms.