Fall blooming bulbs are the tiny treasures of the autumn garden. As the days shorten and the shadows lengthen, the autumn crocus and colchicum make their début. As much as the spring crocus herald the coming of Spring and the end of winter, the autumn crocus announce fall is coming, time for warm sweaters and long walks, good books and homemade soup. It's time to gather your harvest in, and collect flowers to dry as airy keepsake of the glorious summer we've enjoyed.
Autumn crocus and colchicum bulbs are planted in late summer to early fall with their blooming period to follow immediately afterwards. They should be planted with bonemeal to feed the bulb and encourage blooming and planted in a mostly sunny location with well drained soil. They look great tucked into rock gardens, around pavers and at path edges.
Autumn crocus, like their spring blooming cousins, grow about four to five inches tall while colchicum flowers are larger and rise a bit higher to about eight inches in height. Autumn crocus and colchicum bloom without leaves leading to common names such as naked crocus but they are quite beautiful in their simplicity. Their leaves do not appear until spring, arising then without flowers, but as an important developmental phase of the bulbs. After three or four years they may benefit from division which should be done right after foliage starts to die down in spring.
Colchicum are a large bulb measuring two to three inches across and should be planted about 3 inches deep. Colchicum 'The Giant' is a lovely lavender-pink single variety that actually looks a lot like a very large crocus which is probably why they are often confused. Colchicum 'Waterlily' has spectacular double pink blooms which really do resemble water lily blooms. Both varieties are strong growing and multiply quickly.
Autumn crocus are a much smaller bulb, about the same size as spring blooming crocus (about ¾ of an inch across) and should be planted 2-3 inches deep. Varieties include Crocus speciosus which has showy violet-blue flowers, C. zonatus (also known as kotschyanus) which has pink blooms, the more rare C. lutea which has darling, bright yellow flowers and the saffron crocus or botanically, Crocus sativus, has lilac flowers and whose stigmas are harvested for the spice saffron. To harvest your saffron simply pick the stigmas as soon as the flower opens, dry them and store in a jar.
Whichever fall blooming bulbs you might decide to give a try and I know that you will enjoy them all and consider them tiny treasures that signal the coming of autumn.