These low growing compact plants can be used to bring dashes of colour to sunny beds, borders, rock gardens and containers. They also naturalise well in grass or amongst other low growing plants.
The hardy six-petalled, goblet-shaped flowers, spring up through thin grass like leaves from autumn to spring (depending on the variety). Most UK gardeners grow early spring flowering types, however, with careful selection crocus blooms can be grown almost in succession from September through to April. A wide range of flower colours are available, depending on the variety, species and hybrid selected.
The name Crocus derives from the Greek "krokos" meaning saffron. Originating from the thread-like red stigmas of the Crocus species C. sativus.
Family: Iridaceae (Colchicum species are from the Liliaceae family).
Height: from 2 to 4in (5 to 10cm), depending on variety.
Hardy: Hardy in most situations.
Soil Type: Tolerant of most well drained soil types.
Crocuses are ideally suited for rock gardens, sunny borders, pots, containers, raised beds or for naturalising in the wild garden. Many types can also be grown as house plants, in pots or bowls, provided they are not taken into the warmth of the house until some colour is showing in the buds. Plant outside immediately after the flowers fade.
All varieties required a reasonably fertile, free
draining soil, and an open sunny aspect.
Plant the autumn flowering varieties in early summer.
Plant winter and spring flowering varieties in the
Plant the corms with at least an inch of soil covering them.
The flowers of autumn crocuses appear before the leaves. So plant these in an open sunny site, where they will be baked in the summer sun. Thus ensuring good flowers the following season.
These versatile and easy to grow bulbous plants require a light free draining soil. Fertilise with a little bonemeal or similar slow release fertiliser during the growing period.
Crocuses naturalise well if the growing conditions are right. The foliage will die back after flowering and disappear until the following year. Early flowering varieties are ideal for naturalizing in grass. Mowing should be delayed until the flowers and foliage have fully died down.
Crocus corms are increased by offsets or by sowing seed.
To propagate named varieties, dig up the corms when dormant, then remove and replant the offsets.
Seed can be sown in autumn. Sow ripe seed in trays of light sandy loam and place under shelter out-of-doors, until late autumn. Protect in a cold frame over winter, then plant out the following autumn in a reserve bed. Offsets can flower the following season but seedlings usually take three or four years to bloom.
Note: The seeds and corms of Colchicums are poisonous.
There are many species and varieties of these colourful flowering plants.
C. kotschyanus (zonatus), pale lilac pink flowers (September). Ideal for naturalizing.
C. sativus (Saffron crocus), purplish-lilac flowers veined violet with bright red centre (September, October).
C. byzantinus, purple lilac flowers (September, October).
C. speciosus (large autumn crocus), many coloured varieties (September, October).
C. speciosus aitchisonii, bright blue flowers, with
C. speciosus albus, white flowers.
C. longiflorus, lilac scented flowers (October-November). Long flowering period.
C. medius, lilac-purple flowers (October-November).
C. banaticus, blue-purple flowers (early autumn).
C. ancyrensis, orange yellow flowers (February). An ideal container variety.
C. aureus, yellow flowers (January, February). Easily propagated by seed.
C. etruscus, blue-violet flowers (February).
C. laevigatus, pale lilac (January).
C. imperati, lilac and brown striped flowers (January, February).
C. ochroleucus, creamy-white flowers with orange base (November, December).
C. sieberi 'Hubert Edelsten', violet-purple flowers with a yellow throat and white bands on outer petals (January to February).
C. biflorus, mostly white flowers (February, March).
C. chrysanthus, golden-yellow rounded flowers (January to March). Good rock-garden plants.
C. susianus (cloth of gold) orange flowers, veined with bronze (February to March).
C. tomasinianus, dainty blue-violet flowers (January
to February). Good for naturalizing (self seeds freely).
Ideal for the rock garden.
C. versicolor, white flowers, with purple stripes (March).
C. aureus, shades of yellow, blue and purple, also white and striped (February - April).
C. minimus, deep purple and lavender flowers (late Spring). A miniature species 2in (5 cm) high, well suited to the rock garden.
C. vernus (Dutch crocus) shades of purple and lilac flowers (early to late spring).
C. biflorus (Scotch crocus) Flowers white or blue with purple veining (early spring).