I write about colchicums almost every summer because they are so easy to grow and are so important for fall colour. August is the only time of year to plant these September-blooming crocus that also go by the name Autumn Crocus.
It’s so nice to see fresh colour popping out of the ground so quickly after being planted.
Colchicum bulbs become huge and can, over time, produce 19 to 25 flowers, one right after the other, until they all open in a profusion of colour.
A lady who used to grow thousands in her backyard in Vancouver told me it takes about two years for a small bulb to grow into a huge specimen, at which point it splits into four smaller ones.
Small bulbs will produce five to seven flowers, while mid-sized bulbs will have about a dozen blooms.
I have learned the hard way that these bulbs love a sunny, well-drained, yet moist location, with average soil.
One year we planted them in several shady spots, only to have them gradually deteriorate to the point of no return.
You can leave them in the ground to naturalize, if that is the effect you wish to have.
A single corm of a large colchicum hybrid can easily multiply to cover nearly 900 sq. cm. of garden.
Just imagine what a few well-placed groupings throughout your garden can do. It is best to plant them about 10 cm deep and about 15 to 20 cm apart. They need some room, not only to multiply, but also for the huge foliage which will develop the following spring.
