Jefferson Seed Library

Cleome

Also known as the spider flower or grandfather’s whiskers, cleome is a low maintenance flower that is loved by pollinators and hummingbirds alike. 

  • Color
Dark Fuschia
  • Scientific Name
Cleome hassleriana
  • Growing Level
Intermediate to Easy
  • Seed Saving Level
Intermediate
  • Seed Storage
2-3 years if properly stored
  • Life Cycle
Annual
  • Germination Time
8-12 days
  • Germination Teperature
70-80 F
  • Cold Stratification?
Helpful
  • Height
3-5 feet
  • Light Requirements

Needs light to germinate

Full sun

  • Blooms in
Summer through Fall
  • “Check Out” Month See Upcoming Events for specific “check out” dates. 
April, May, and June
  • In Stock?
No

 

Cleome

Growing Tips

Container Friendly
Trap Crop

When to Start

 

Cold Stratify: 7-14 days before starting seeds.

Spring: Start indoors, after cold stratifying the seeds, 4-8 weeks before the last frost date and soil temperatures have warmed to 70-80 F. (About 2 weeks after the last frost date. Mid-May for Jefferson, GA)

Direct Sow: After cold stratification and the danger of frost has passed. Wait until soil temperatures have warmed to 70-80 F before sowing. (Mid-May for Jefferson, GA)

How to Grow

 

While it isn’t necessary to cold stratify the seeds, they do benefit from 1-2 weeks in the refrigerator before sowing. Seeds can be started indoors, however, transplanting can be a problem and the seedlings may not survive. Wait until the seedlings are around 6 inches tall to transplant to give them the best chance. It is recommended to direct sow the seeds after cold stratification and the soil temps have warmed to 70-80 F. In a typical year, this is about 2 weeks after the last frost has passed.

The seeds need light to germinate. Gently press the seeds into the soil of a full sun bed. Or lightly cover them with soil to keep them from blowing away.

Once they are 1-2 inches tall thin them to 6-8 inches apart. Then thin them again to about 2 feet apart once the seedlings are established. Rows should be spaced 18 inches apart.

 

How to Cold Stratify

If starting seedlings, sow into seed cells. Gently press the seeds into the seed starting mix. Place the cells into a plastic bag and place them in the refrigerator for 1-2 weeks. Keep the soil moist but not soggy. Monitor it to make sure no mold starts to grow. After this time, place them under grow lights. Keep the soil moist but not soggy. A heat mat might be needed as seeds germinate with soil temperatures between 70-80 F.

If direct sowing, place the seed packet into the refrigerator for 1-2 weeks. Then direct sow according to the directions above.

 

Care

 

Use mulch to help retain soil moisture and suppress weeds. The soil should be moist but not soggy. Cleome will tolerate dry conditions, but by keeping the soil moist the plant will bloom better and put on more foliage. Typically the plants don’t require staking unless they are a taller variety. An exception is if you live in a windy area. The flowers should bloom until a frost. They make beautiful annual hedges and add depth to a garden when placed in the back. They are also very impressive in mass plantings. Cleome is prickly and some varieties are thornier than others. To create shorter more compact plants, pinch back when they are young.

The plants can be removed after a hard freeze. Gloves are recommended due to their prickly nature.

 

Using as a Trap Crop

Cleome can be as a trap crop for stink bugs. To learn how to do trap cropping, check out the video Trap Cropping!

Seed Saving

Isolation Distance

 

Cleome is insect dependent for pollination and will cross-pollinate with other varieties. Isolate varieties by 1/2 mile to prevent cross-pollination.

 

Instructions

 

Select healthy, robust plants free of any signs of disease or insect infestation for seeds. Seeds carry the traits of the parent plant. Choose plants that exhibit the traits you wish to preserve. Consider bloom size, color, and shape, as well as blooming time.

Allow the biggest and healthiest blooms to mature on the plant. Once the seed pods have turned yellow they can be removed from the plant. Dry pods will often burst open.

Gently split the pod apart and remove the seeds. Remove plant debris by hand.

 

Special Note:

Seeds will often not produce true-to-type and after a few generations, the blooms will be light pink.

Features

  • Attracts pollinators
  • Attracts hummingbirds
  • Fragrent
  • Low maintenance 
  • Good cut flower
  • Container friendly
  • Drought tolerant
  • Heat tolerant

If stink bugs are an issue for you, try using cleome as a trap crop to help control the stink bugs. 

You May Also Like: 

Balloon Flower

Starting Seeds Indoors

Cold Stratification

Trap cropping: How to keep pests out of your main crop.

Frost and Freeze Dates

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