When to Plant Crocus
Plant crocus corms in the 3 weeks after your first fall frost; they root over winter and bloom the next spring.
Crocus at a glance
- Plant in fall
- in the 3 weeks after your first fall frost
- Second marker
- Your first hard freeze (28 °F)
- Time to bloom
- Late winter to early spring
- Spacing
- 16 per square foot
- Frost
- Takes hard frosts
Growing crocus
Crocus are the first flowers of the year in many gardens, opening in late winter or very early spring on sunny days. The corms are small and cheap, so plant them by the dozen in lawns, under trees that leaf out late, or at the front of a bed. Bees out on the first mild days visit the open flowers.
Fall planting and the hard freeze
Crocus corms are planted in fall with the other spring bulbs. Following UW–Madison Extension, plant when the soil has cooled to about 50 to 55 °F and stop a couple of weeks before the ground freezes. In frost terms that is from your first fall frost to three weeks after it; the first hard freeze (28 °F) usually arrives in between, a median 11 days after the first frost. Crocus need a winter chill as well. The UC Master Gardeners of Marin County, in zones 9 and 10, chill the corms in the refrigerator for one to three months before planting, so from zone 9a on this page gives that advice instead of dates.
Sources: UW–Madison Extension: Plant bulbs now for spring color and UC Marin Master Gardeners: Focus on crocus. Hard freeze dates: NOAA 1991–2020 climate normals.
Dates by hardiness zone
Typical dates for each zone; your ZIP code gives your own.
| Zone | Plant | First hard freeze |
|---|---|---|
| Zone 3a | Sep 14 – Oct 5 | Sep 26 |
| Zone 3b | Sep 25 – Oct 16 | Oct 3 |
| Zone 4a | Sep 28 – Oct 19 | Oct 7 |
| Zone 4b | Oct 1–22 | Oct 11 |
| Zone 5a | Oct 5–26 | Oct 16 |
| Zone 5b | Oct 10–31 | Oct 22 |
| Zone 6a | Oct 16 – Nov 6 | Oct 28 |
| Zone 6b | Oct 22 – Nov 12 | Nov 1 |
| Zone 7a | Oct 25 – Nov 15 | Nov 4 |
| Zone 7b | Nov 1–22 | Nov 12 |
| Zone 8a | Nov 7–28 | Nov 19 |
| Zone 8b | Nov 13 – Dec 4 | Nov 28 |
| Zones 9a–11b | Winters here are too mild to chill crocus in the ground. Keep the corms in the refrigerator for one to three months, then plant them in late fall or early winter. | |
Questions about crocus
Can I plant crocus in my lawn?
Yes. Most crocus finish blooming before the first mowing. If the leaves are still green by then, mow around them until they turn yellow, so the corms can store food for next year.
Why did my crocus not come up?
Squirrels and voles like to dig up the corms. Planting them a little deeper, or under a piece of wire mesh laid flat on the soil, keeps more of them safe.
