There's something delightful about fall flowering crocus. No matter how long you grow them, they always surprise you in fall with their bright, cheery flowers. Maybe it's because we don't expect them this time of year or because they stand out with the lack of other brightly-colored flowers in the garden, but they seem to shine each autumn.
All About Fall Flowering Crocus: Varieties and Uses
Fall flowering crocus fall into two categories. The small-flowered types, such as edible saffron crocus, have flowers much like their spring flowering cousins. The flowers appear followed by the grass-like foliage either at flowering or later in fall. These crocuses come in colors such as white, purple-blue and lilac. Most are hardy in USDA zones 6 to 9, but there are some species that can grow in the colder climates of USDA zones 4 and 5.
The most common fall crocus is the edible saffron crocus (Crocus sativus). Lilac purple flowers appear in September in cold areas and later in fall in warmer locations. It's hardy to USDA zone 5. The thin red filaments in the pistil of the flower can be delicately removed with a tweezer and used in cooking – these are the same saffron threads that you find in the spice aisle. Or you can harvest the flowers when open and do the tweezing indoors. To dry saffron, place it in an oven on low heat until the filaments are light and breakable. You can also lay them out on a table in a dry room, out of direct sun, for a few days to dry.
There are other fall flowering crocus similar to saffron crocus that are grown just for their beauty. Crocus specious is the hardiest of the small fall flowering crocus, surviving in USDA zone 4 climates. They have blue to mauve colored flowers. There is a white flowering version as well with snowy colored blooms and yellow stems. Crocus pulchellus is similar to the species crocus, but has a pale lilac colored flower with purple veins.
The other group of fall flowering crocus are really not crocus at all, but a type of lily. Colchicum have the common names autumn crocus and naked ladies because of the way they grow. The flowers emerge in fall and the foliage appears the next spring. Hence the common name “naked ladies”. Colchicums have larger-sized flowers than saffron crocus. They burst from the ground in September and October putting on quite a show when planted in groups.
Most colchicums are hardy to USDA zone 5. The flowers are white, pink, blue, purple or rose depending on the variety. The flowering is enhanced because each bulb will send up a bouquet of flowers on 5 to 10 stems. The flowers stand 6 to 8 inches tall making a statement in the garden. Look for different-colored varieties. 'Mauve Wonder' produces soft purple colored blooms. 'Water Lily' has double pink colored flowers. 'Autumn White' has pure white blossoms. 'Rosy Dawn' produces rose color blooms. After flowering the bulbs (corms) go dormant until spring. Then they send up broad leaves to collect energy from the sun and rejuvenate the bulb for the fall. The leaves yellow and fade by summer.
All About Fall Flowering Crocus: In the Garden
Plant the small flowered fall crocus in rock gardens, under trees, around shrubs, and in the ground to cover patches, or even directly in the lawn. In the lawn, let the foliage emerge and naturally yellow without mowing it. This will work fine in many colder areas, since the lawn is growing slowly in autumn. In the flower garden, plant them where their colorful blossoms will pair nicely with other fall flowers such as sedum and dwarf aster.
The larger colchicum bulbs can be planted in among evergreen ground covers and in the perennial border. In a rock garden they can flop over, especially if not grown in full sun. They shine when planted among vinca, ivy and other evergreen ground covers because their bright flowers contrast well and are supported by, the sturdy green ground covers. Plus, the ground cover prevents soil from splashing up onto the flowers, keeping them clean looking until they fade in a week or so.
All About Fall Flowering Crocus: Additional Tips
Small flowered fall crocus can also be planted in containers. Plant in later summer in a container with good drainage holes filled with moistened potting soil. Place in a sunny location and keep evenly moist. After flowering, let the foliage emerge. In cold areas, protect the containers by bringing them into an unheated garage or basement for winter.
When planting fall flowering crocus, plant the bulbs (corms) twice the diameter of the bulb deep. For small fall crocus, this is about 3 to 4 inches, while colchicums can be planted up to 4 to 6 inches deep. Plant on the deep side in sandy soils and shallow side in clay soils. Plant in groups for the biggest visual impact. After a late summer or early fall planting, fall flowering crocus should bloom in about 4 to 6 weeks depending on your climate.
About the Author: Charlie Nardozzi is a nationally recognized garden speaker, author, consultant, radio and TV show host. He delights in making gardening information simple, easy, fun and accessible to everyone. Visit his website, GardeningwithCharlie.com for how-to gardening information, and for more about Charlie.