How to Grow Saffron Crocus: Planting Corms for Fall Flowers

Plant saffron crocus corms in September or October, 3 to 4 inches deep, in full sun and well-drained soil, and expect fall flowers. Penn State calls the saffron crocus (Crocus sativus) a fall-blooming perennial corm, not a bulb, in the iris family, and says it thrives in USDA zones 6 through 9. NC State says it is subject to fungal disease if the bloom period is wet and to root rot in a wet site, and that squirrels, mice and other rodents may eat the corms. This guide covers it as an ornamental fall-flowering corm for the garden.

USDA zones

6–9 (Penn State)

Sun

Full sun

Lifecycle

Perennial

Origin

Middle East

Soil

Well drained, moderate organic matter

Planting depth

3–4 in (NC State 4 in, Penn State 3–4 in)

Spacing

3–4 in apart

Bloom time

September to October, about 15 days

Not the same as autumn crocus

Colchicum autumnale is also called autumn crocus. It is a different plant, and it is often mixed up with the saffron crocus. When you buy, look for the botanical name Crocus sativus.

What the saffron crocus is

Penn State says the saffron crocus is a corm, not a bulb, and that it is a sterile triploid, which makes it unable to produce seeds. It propagates by its corms instead. NC State says the corms multiply each year and can be divided to produce more plants. For a gardener this means every plant comes from a corm, and a patch grows by division rather than by self-seeding.

Sun, soil and site

NC State says to plant in well-drained soil with moderate organic matter, in full sun. It says the plant is subject to root rot if planted in a wet location.

When and how deep to plant

Penn State says to plant in September through October. Illinois Extension says it is planted at the same time as spring bloomers so that it may receive a cold treatment before flowering. For depth and spacing, NC State says corms should be planted 4 inches deep and 4 inches apart, and Penn State says 3 to 4 inches deep and 3 to 4 inches apart.

1. Buy corms from a reputable grower. Penn State advises this. Look for Crocus sativus by name.
2. Plant in September or October. Illinois Extension says it goes in with the spring bloomers so it gets a cold treatment before flowering.
3. Set them 3 to 4 inches deep. 3 to 4 inches apart (Penn State), or 4 and 4 (NC State).
4. Choose full sun and good drainage. Well-drained soil with moderate organic matter (NC State).

How long they bloom

Illinois Extension says that in September and October the plant blooms for about 15 days. NC State describes the flowers as appearing in fall. Because the bloom is short and comes in autumn, it fits among other fall flowers; our bloom calendar shows what else is flowering then.

Common problems

Grow these next

Saffron crocus is planted in fall with the spring bulbs, so our tulip guide and the fall bulb planting guide fit the same planting day. For another plant from the same family, see the iris guide.