Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
Cleome, or Spider Flower, has been a cottage garden favorite for many years. If you have a butterfly garden or a hummingbird feeder, you will want to plant these beauties which attract both butterflies and hummingbirds.
What are Cleome?
Cleome (Cleome hassleriana) are native to the southern countries of South America. They are only hardy in zones 10 and 11 so they are grown as annuals in all regions of the US. In their native areas, they are pollinated by bats. Here in the US, they attract a number of different beneficial insects including butterflies and hummingbird moths.
Cleome are nick-named Spider Flower for good reason. Their flowers, which come in white, pink and purple, grow in an umbel shape like an umbrella with long stamens which stick out giving them a spiky look like the legs of a spider. Bloom-time is June. The plants will continue blooming until frost without deadheading. Instead, the flower stalk continues to grow, becoming longer and longer.
After flowering, they develop long, bean-like seed pods which you might want to pinch off because they self-sow prolifically and can easily become a nuisance. If you wish to collect the seed, wait until the pods have dried and turned yellow. If left on the plants, the ripe pods shatter, scattering their seeds all over your garden. If allowed to self-sow, over several generations the flowers will lose their distinctive colors and become a uniform pale pink. Personally, I don’t mind but some gardeners prefer their cleome to be the original colors that they planted. In that case, the seed pods should be removed before they ripen and scatter their seeds.
Cleome leaves grow in fan-shape groups like a hand with the fingers spread out. When they are not blooming, they are occasionally mistaken for marijuana plants.
The stems develop thorns so it is recommended that you not grow them near paths or sidewalks. They also have a scent which some people find offensive so you might want to plant them away from windows and outdoor living areas. Personally, I have never found their scent to be offensive.
Depending on the variety, cleome can attain a height of 3’ to 5’ when full-grown. The heirloom Queen series are the tallest while the newer Sparkler series are shorter and can be grown in containers. The Queen series are an excellent back-of-the-border plants. The Sparkler series has a longer blooming period than the older Queen series. Despite its drawbacks, my favorite is the old-fashioned Queen series. They don't get lost among the tall cosmos and nicotiana that I also grow.
How to Grow Cleome
Cleome do best in full sun. When grown in partial shade, they become leggy and fall over. They grow well in average soil, needing little in the way of fertilizer. Too much fertilizer will result in leggy plants. They are an excellent addition to your xeriscape because they are drought tolerant. A thin layer of mulch, 1 to 2 inches, will help the soil to stay moist. Avoid over-watering your plants. They are also deer resistant for those of us who have a deer problem. Rabbits are not fond of them either if you have problems with rabbits.
How to Grow Cleome From Seed
Cleome are usually grown from seed. The easiest way is to direct sow them in your garden after all danger of frost has passed. Alternatively, you can sow seeds in the fall for germination in the spring. The seeds need light to germinate, so sow them on the surface of the soil. Do not cover them. When the soil temperature reaches 70⁰F to 74⁰F, the seeds will germinate within 1 to 2 weeks. Thin your seedlings to 18 inches apart.
You can also start your seeds indoors 4 to 6 weeks before your last frost. Surface sow the seeds because they need light to germinate. Use a heat mat to keep the soil temperature at 70°F to 74°F. You can expect germination within 1 to 2 weeks. Plants started indoors can be set out into your garden after all danger of frost. Plant your seedlings 18 inches apart. Depending on when they were planted, you can expect flowers by mid- to late-June.
Cleome have all the characteristics of classic cottage garden flowers. They are easy to grow, attract butterflies, hummingbirds and beneficial insects and are virtually disease free. Their only true failing is their tendency to profusely self-sow in your garden.
© 2014 Caren White
Caren White (author) on July 07, 2014:
It was new to me too that they attract hummingbirds. Thanks for the vote and the pin.
FlourishAnyway from USA on July 07, 2014:
Beautiful and it's nice to know that it attracts hummingbirds. We have several feeders and enjoy watching them from afar. Voted up and pinning to my Garden board.
Caren White (author) on July 05, 2014:
I was disappointed that none germinated in my garden this year and then I realized that I had covered the seed! Thanks for reading and voting tobusiness.
Jo Alexis-Hagues from Lincolnshire, U.K on July 05, 2014:
Beautiful flower, I've been meaning to grow Cleome from seeds, thank you for the reminder. Voted up, beautiful and useful.