Bulbs: fall flowering crocus
Technically members of the iris family, there are about 30 species of crocus that bloom in fall and winter. Hybridizers have concentrated on the familiar spring-blooming crocus that now outnumber the fall bloomers.
Fall-blooming crocus are reliable jewels sure to thrive in any garden. The bulbs, technically called corms, are planted during the brief July and August dormant period. All crocus mentioned here are hardy to USDA zone four.
The saffron crocus is the most familiar due to its history of culinary, dye, and medicinal uses. It's also the most commonly available species. The broad, six- to twelve-inch long leaves grow briefly in the spring and then die by midsummer. In the fall, leafless flower stalks rise to produce clusters of flaring, four-inch purple flowers. A white variety is also available.
Other fall-flowering crocus species include goulimyi, kotschyanus, medius, pulchellus, ochroleucus, and speciosus. You can obtain these less commonly available species from mail-order bulb companies. They also might be available at local garden centers and nurseries.
Plant fall-flowering crocus eight inches deep in well-drained soil in July or August. Add sharp gravel around the corms to deter rodents. Because these corms can be planted so deeply, you can plant ground covers or other plants with an open nature over them. As they poke through in the autumn, the flowers can accent the contrasting color foliage.
For more information, see the following Colorado State Extension fact sheet(s).
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Updated Friday, April 19, 2013