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Plant of the Week
Autumn Crocus
Latin: Colchicum autumnale
 Even in difficult drought years like this one, our gardens can
amaze and amuse us. We see tough little plants do their thing under some of the
most adverse conditions imaginable. One of these durable little plants is the
autumn crocus, which recently began blooming -- a reminder that droughts always
pass and better days lie ahead.
The soft pink flowers grow about 8 inches tall with blooms 3 inches across. As
the plants become established, each corm may produce three to eight stems, each
bearing a single flower. The corms are 3 inches across and poisonous.
The plant blooms without foliage. It just appears, as if by magic, as the
hottest days of summer begin to pass away. The foliage is broad and almost hosta-like
in appearance. It emerges in late winter and withers away with the first hot
days of May and June.
White-flowered and double-flowered selections are available, as are hybrids such
as ‘Autumn Queen’ (violet), ‘Lilac Wonder’ (pinkish-lilac) and ‘Waterlily’
(double-form, lilac mauve).
The autumn crocus is not really a crocus. It’s a member of the lily family. It’s
widely distributed from northern Africa through southern Europe.
Colchicums have long been favorites of gardeners, but before that they were
favorites of the early doctors who used them for various medical treatments. The
bulbs produce a toxic alkaloid called colchicine that’s still used today to
treat gout and rheumatism.
But colchicine also has a part to play in creating new and improved garden
plants.
In 1931, a Bulgarian scientist experimenting with eggplant in his greenhouse
used a nicotine spray to control a bug problem he was having. Upon examining the
seedlings of those eggplants, he discovered that many seedlings had undergone
chromosome doubling -- the creation of tetraploids. This started other
scientists looking at related compounds. In the mid-1930s, the husband and wife
team of Nebel and Nebel from Geneva, N.Y., discovered that colchicine was the
most effective at causing this doubling phenomena.
When plants have extra chromosomes, they usually have larger characters: bigger
flowers, bigger fruits and larger, thicker leaves. The strawberry, for example,
has eight sets of chromosomes that arose naturally from chance doubling and
crossing.
With the discovery of colchicine, David Burpee’s plant breeders, caught up in
the "better living through chemistry" mania that swept post WW II America, began
using the drug to double the chromosome numbers of most of their major crops.
Their tetraploid snapdragon appeared in 1946 and was soon followed by the
enormous cactus-flowered zinnias and tetraploid marigolds. This bigger-is-better
philosophy has been carried to extreme in some plants. The delicate beauty of
the flower is lost to a Frankensteinian rendition of its former self. In the
garden, one would hardly suspect the role that the lovely autumn crocus played
in the sex life of marigolds and zinnias.
Colchicum is best planted in sunny or partly shaded sites in well drained soils.
The corms are planted with the nose of the corm 2-3 inches deep in drifts of a
dozen or more. Because the foliage is large, plants should be given at least 8
inches on center spacing. Once planted, the plants should remain undisturbed as
long as they are thriving.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
September 15, 2000
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