How to Grow Cleome
Cleome At a Glance
Difficulty
Easy
Category
Flower
Sun Exposure
Full Sun
Frost Tolerance
Frost Tender
Cold Hardiness
Survives to 5°C
Plant Family
Cleomaceae
Growing Season
Warm Season
Plant Lifecycle
Annual
How to Start It
★ Recommended for beginners
Sow about 1 week after your last spring frost, once the soil is warm, right where the plants will grow, since cleome has one long main root and does not like being moved. Keep the seeds in the fridge for about a week before sowing to help them sprout, then press them onto the soil and cover them no deeper than 0.5 cm, because they sprout best with a little light. They come up slowly, in 10 to 21 days. Thin them (pull the extras so each has room) to 45 cm apart.
Cleome, also called spider flower, grows tall fast, often over 1 m, with airy flowers that bloom from midsummer until frost. Once it is in your garden, it drops seed and comes back on its own every year. Many older types have small thorns on the stems and a musky smell, so plant them where you will not brush past them, or choose a newer thornless type.
When To Start
Cleome needs warmth. Wait until your last frost has passed and the soil has warmed before sowing.
We do not have exact sowing dates for this one yet.
When should you plant Cleome?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Cleome Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Cleome Calendar
Set your location to turn these into exact dates and reminders.
Sow cleome outdoors now that the soil is warm
1 week after your last frost· every year
Cut off cleome seed pods to stop it seeding everywhere
75 days after your last frost· every year· optional
Did you water your cleome seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Hello from your cleome! Thin the seedlings so each plant has room to grow tall.
About 30 days after you plant it
Cleome check! Water deeply in dry spells as the tall stems get ready to flower.
About 90 days after you plant it
The Journey Ahead
Cleome's Lifecycle
Seedling
Mature Plant
Seed Production
Step 2
Planting & Sprouting
Expect sprouts in 10–21 days
Growing Tips
- 1Give cleome full sun, at least 6 hours a day, and plant it at the back of a bed where its height shows off.
- 2Average soil with a little compost is perfect, because rich soil makes the stems tall and floppy.
- 3Water young plants often, then only in long dry spells, since grown plants handle drought well.
- 4It needs almost no feeding: a little compost tea in early summer is enough.
- 5In windy spots, give the tallest plants a stake.
- 6Wash aphids off with a spray of water, and wear gloves around thorny types.
Seedling Phase
Step 3
Growth & Maturity
150 cm
Mature Height
50 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
When to Pick
Blooms midsummer to frost; the flower spires keep rising and opening
How to Harvest
- 1Cleome mostly looks after itself once it is growing.
- 2It keeps blooming at the top as the stems grow, so you do not need to snip off faded flowers.
- 3Cut off the long, thin seed pods below the flowers if you do not want hundreds of seedlings next spring.
- 4For the vase, cut stems when the first flowers open, and they last about a week.
- 5Pull the plants after frost, and watch for seedlings in spring, which you can thin or move while they are small.
Step 5
Saving Seeds
How to Save Seeds
Cleome makes long, thin seed pods below the flowers, and seed from older types grows much like its parent, though colours can mix. Some newer thornless types make little or no seed. Pick the pods when they turn tan and dry, just before they split, and open them over a bowl. Let the small seeds dry a few more days, then store them in a labelled envelope somewhere cool, dark and dry. Or simply let the pods drop their seed, and cleome will sow itself for next year.
Seed Production
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