The Three 'C's' Among Fall-flowering Bulbs: Colchicum, Crocus and CyclamenBy Todd Boland (Todd_Boland)
August 27, 2011
(Editor's Note: This article was originally published on November 24, 2007. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Gardeners generally associate bulbs with springtime displays of tulips, daffodils, hyacinths and crocus. However, some bulbs actually begin to flower in fall, just as most plants are going dormant. There are actually many types of bulbs that produce their flowers during the autumn months, but the most popular are colchicum, crocus and cyclamen; the three ‘C’s’ among the fall blooming bulbs.
Perhaps the best known of the fall-flowering bulbs are the Colchicum. Commonly referred to as the autumn crocus or meadow saffron, colchicums are not related to crocus at all, but are actually more closely related to lilies. Beginning in mid-September and continuing into November, colchicums produce large, goblet-like blooms in shades of pink, violet or white. In spring, colchicums offer relatively large, broad leaves, which are, unfortunately, a favorite food source for slugs and snails.
There are quite a number of fall-flowering colchicums (there are also some spring-bloomers) but they are often hard to find locally, so mail-order nurseries are probably the best source. Among the more available species are Colchicum autumnale, C. speciosum, C. byzantinum and C. agrippinum. Hybrids include ‘Autumn Queen’, ‘Lilac Wonder’, ‘The Giant’, ‘Violet Queen’ and the double-flowered ‘Waterlily’. These are all hardy to at least USDA Zone 5, maybe colder if given extra winter protection.
A selection of Cochicum species (left to right): C. autumnale 'Album', C. agrippinum, C. speciosus 'Album', C. speciosus, C. byzantinum
Some Colchicum hybrids: C. 'Lilac Wonder', C. 'The Giant' and C. 'Waterlily'
Another popular group of fall-flowering bulbs is the true autumn Crocus, relative of the typical spring crocus. The earliest species bloom in mid-September, while other varieties may not bloom until December; during mild falls I’ve actually picked autumn crocus on Christmas Day! Like their spring-blooming cousins, fall crocus produce narrow, grass-like leaves, either in the fall after flowering or in the spring. Although there are a surprising number of autumn-flowering crocuses, most are only hardy in USDA Zones 7-9. However, there are a few that can survive in USDA Zone 4 or 5. The most common and readily available of the hardier species is Crocus speciosus, with purple-blue flowers from October till December. Crocus kotchyanus (lilac) and C. nudiflorus (dark purple-blue) are also quite hardy. In milder zones, try C. ochroleucus (white) C. longiflorus (silvery-lilac), C. serotinus (silvery-lilac), C. tournefortii (lilac), C. niveus (white), C. pulchellus (silvery-lilac), C. medius (lavender-blue), C. sativus (the real meadow saffron; light purple-blue) or C. goulimyi (lilac).
Among the hardiest fall crocus are C. speciosus, C. nudiflorus, C. kotchyanus and C. longiflorus
Slightly more tender are C. ochroleucus, C. tournefortii, C. serotinus and C. goulimyi
The other fall-flowering bulb, Cyclamen, is perhaps the most dainty of the fall bloomers, offering a profusion of pink or white flowers shaped vaguely like a shuttlecock. They bloom from late August through early November. Unlike many fall crocus or colchicum, cyclamen produce their leaves just before, during or just after flowering. These leaves stay green through the winter months and do not disappear until June or July. Their leaves are often attractively marbled light green to silvery over a dark green background. The most popular species is Cyclamen hederifolium. They are available in numerous named forms, based primarily on leave color and shape. They are hardy to USDA Zone 5. The earliest of the fall-blooming cyclamen is C. purpurascens, which actually begins to bloom in August. It is the hardiest (USDA Zone 4) and one of the few fall-bloomers with fragrant flowers. In USDA Zone 6 or milder you can grow C. intaminatum, the smallest-flowered cyclamen with white or pale lilac flowers. Also with small, dainty flowers is C. cilicium. Perhaps the largest-flowered fall cyclamen is C. graecum. However, this one is also quite challenging, as they need to bake dry in summer to encourage flowering.
Some cyclamen species: C. hederifolium, C. hederifolium 'Album', C. purpurascens, C. intaminatum
The fall-flowering bulbs require moderately fertile, well-drained soil (a heavy wet soil will quickly cause them to rot). Select a reasonably sunny site for colchimum and crocus as their flowers only open when exposed to sun. Cyclamen prefer part shade. Crocus should be planted about 7 cm (3”) deep. Colchicums have quite large bulbs and should be planted about 10-15 cm (4-6”) deep. Cyclamen, on the other hand, should be planted with no more than 2 cm (1”) of soil over the top of the tuber. When first planted, generally in early September or even August if possible, the addition of bonemeal or a high phosphorous fertilizer, is beneficial. In early spring, the addition of a general garden fertilizer or good compost will further add to the plant’s longevity. As with the spring bulbs, allow their foliage to die down naturally so the bulbs can accumulate the reserves necessary for future bloom.
Autumn crocus, colchicum and cyclamen are ideal for the rock garden where their fall flowers are easily seen among the other low-growing plants. While the leaves of crocus and cyclamen are relatively tidy, colchicum foliage is so large and floppy, that many gardeners find them unsightly in the rock garden. One exception is C. agrippinum, whose foliage is relatively small and an interesting grey-green color. This species also offers checkered pink flowers, a unique feature among colchicum.
Crocus and colchicum are also suitable for planting among low groundcovers such as periwinkle, creeping jenny, creeping thyme or bugleweed. The advantage of this setting is that the groundcovers prevent autumn rains from splashing mud onto the flowers. True autumn crocus may be naturalized in lawns as long as the foliage gets a chance to ripen before the first spring mowing. Cyclamen lend themselves to woodland settings as they prefer dappled shade.
Examples of uses are rockgardens (C. nudiflorus), growing through groundcovers (C. agrippinum) and woodlands (C. hederifolium 'Album')
At one time, gardeners bought their bulbs in fall and had to wait until spring to enjoy the blooms. By growing some fall-flowering bulbs, the reward is much more immediate.