Crocus spp and hybrids
full sun, part sun
Bloom Period and Seasonal Color
late winter to spring in colors such as blue, white, yellow , purple and bi-colors
Mature Height x Spread
4 to 6 inches x 2 to 4 inches
This low growing, clumping bulb is an early bloomer in the landscape, offering bright colors that signal the end to winter. The lance-shaped leaves emerge as soon as the ground thaws to produce the cup-shaped flowers. There are two different types of crocus. The most popular is the spring blooming crocus in a broad array of colors from white to purple to yellow such as the Dutch hybrids. However, for some fall color, consider planting the autumn crocus that blooms in fall. Saffron is harvested from a fall-flowering crocus species, but saffron crocus are only marginally hardy in many areas of New England. Plus, if you’re thinking of starting a new garden business, it takes 4,000 flowers to make one ounce of saffron.
Where, When and How to Plant
Crocus is hardy throughout our region. Plant spring flowering crocus bulbs (technically called corms) in fall in a full sun location on well-drained soil. Amend the planting hole with a bulb fertilizer and compost before planting. Plant fall flowering crocus in late summer and early fall. Plant the small bulbs 2 to 3 times their diameter deep in groups. Crocus look best when planted close together, so space them just so they aren’t touching.
Keep the soil well watered after planting, Once they are established, crocus are drought tolerant, especially since they go dormant in summer. Let the leaves of crocus bulbs naturally fade after the flowers have past to help the bulb replenish its reserves for next year. Fertilize in fall with a bulb plant food.
Regional Advice and Care
Plant a mix of early and late flowering crocus bulb varieties to extend the flowering season. Crocus will slowly spread over time and naturalize. They rarely need dividing. Voles, mice or chipmunks can eat crocus bulbs. Protect bulbs by spreading crushed oyster or seashells in the planting hole or planting them in wire cages buried in the ground. Avoid using bone meal fertilizer, since it attracts animals. Protect flowers from deer with netting.
Companion Planting and Design
Plant crocus bulbs in front of a perennial flower border or rock garden. Plant close to spring flowering perennials, such as bleeding hearts, that will hide the crocus foliage once it starts to yellow. Crocus also can be naturalized in lawns, under trees or in woodlands. Plant in groups and allow them to spread over time. Plant where they will receive full sun until the leaves come out. If planting in a lawn, don’t mow down the foliage until it yellows after the flowers fade.
For spring blooming crocus varieties, try ‘Blue Pearl’ with its pale blue flowers and a yellow throat. ‘Jeanne d’Arc’ is a pure white flowering heirloom variety with a purple base. ‘Golden Bunch’ is a golden-petaled variety with a tangerine-colored throat. ‘Ruby Giant’ is a large- flowered ruby-colored variety. ‘Cassiope’ and ‘Conqueror’ are blue flowering fall blooming crocus that are hardy to USDA zone 4.
Excerpted from my book, New England Getting Started Garden Guide.