Cleome, commonly called spider flowers, earns its nickname from the long stamens that radiate from each bloom head like thin legs. These tall, airy annuals bring height, color, and steady pollinator traffic to sunny borders, and they keep flowering from early summer until frost. Young plants look scraggly, then transform into dramatic back-of-bed performers once established. Before choosing a site, review the core flower care and maintenance tips for home gardeners, because cleome responds strongly to the light, soil, and spacing decisions made at planting time.
What Is a Cleome Spider Flower?
Cleome belongs to the Cleomaceae family, a small plant group related to capers and mustards. The most common garden species is Cleome hassleriana, a fast-growing annual native to South America that self-seeds readily in warm climates. Plants produce rounded clusters of pink, white, lavender, or rose flowers held above palmate leaves, and the long protruding stamens give each cluster a spidery texture that reads well from a distance.
Height ranges from 3 to 5 feet for most cultivars, with some reaching 6 feet in rich soil. Because the stems are upright and the foliage is open, cleome works best at the back of a border or in the middle of an island bed, where the translucent blooms catch the light without shading shorter neighbors.
Cleome at a Glance
| Attribute | Detail |
|---|---|
| Common names | Cleome, spider flower |
| Botanical name | Cleome hassleriana (Cleome spp.) |
| Family | Cleomaceae |
| Plant type | Annual in most zones; reseeds itself |
| Mature size | 3 to 6 feet tall, 1 to 2 feet wide |
| Sun exposure | Full sun, 6 or more hours daily |
| Soil type | Average, well-drained |
| Bloom period | Early summer to frost |
| Hardiness | Grown as an annual in zones 2 to 11 |
Despite the name, cleome draws no unusual spider activity; the name describes the thread-like stamens, not pests. Gardeners who do find spiders moving indoors should look at the building envelope first. The spider control and prevention strategies for residential construction cover the gaps, vents, and foundation cracks that let arachnids in, and they pair well with the same caulking and screening work that keeps out other insects.
Planting Cleome From Seed
Cleome grows easily from seed and dislikes transplanting, so direct sowing is the most reliable method. In most regions, sow seeds outdoors in early spring after the last frost date, when the soil has begun to warm. Gardeners in mild-winter areas often sow in late fall instead, letting the seeds sit through winter and emerge on their own schedule in spring.
- Loosen the top 6 inches of soil and rake out clumps and stones.
- Scatter seeds thinly, then cover with about 1/8 inch of soil; cleome needs darkness to germinate.
- Keep the surface evenly moist until seedlings appear, usually within 7 to 14 days at soil temperatures of 70 to 75 degrees F.
- Thin seedlings to 12 to 18 inches apart once they hold two sets of true leaves.
- Pinch young plants after the third set of leaves to encourage branching.
Spring Versus Fall Sowing
Fall sowing suits zones with mild winters because the seeds naturally stratify in cold soil and sprout earlier than spring-sown seeds. In cold-winter zones, fall sowing risks frost heaving, so spring sowing is safer. Gardeners who want a head start can start seeds indoors 6 to 8 weeks before the last frost and transplant carefully after all danger has passed, since the taproot resents disturbance.
Cutting gardeners can pair cleome with edible blooms to extend the harvest. Many gardeners grow an edible flower bouquet alongside the border, filling vases with nasturtiums, calendula, and borage while cleome supplies the height behind them.
Popular cultivars give you a choice of stature and color. Queen series plants stay compact at 3 to 4 feet, while the older Cleome hassleriana selections push toward 5 feet. Flower colors range from white and pale pink to deep rose and lavender, so a single planting can carry several tones. Dwarf forms suit the front of a border or a container, and all types produce the same nectar-rich clusters that bees and hummingbirds work from morning to evening.
Caring for Established Cleome Plants
Once established, cleome is forgiving. It tolerates heat, drought, and poor soil better than most annuals, and it keeps blooming without deadheading because the spent flowers drop on their own. Weekly deep watering keeps plants lush; in containers or during heat waves, check moisture more often.
Watering and Feeding
Water at the base rather than overhead to keep foliage dry and reduce mildew risk. A 2- to 3-inch layer of mulch holds soil moisture and suppresses weeds between the tall stems.
- Water deeply once a week, and twice weekly during 90-degree stretches.
- Feed lightly at planting with compost or a balanced slow-release fertilizer.
- Avoid high-nitrogen formulas; they push leafy growth at the expense of flowers.
- Stake tall cultivars in exposed sites, or plant in groups so the stems support each other.
Soil Preferences
Cleome grows in average, well-drained soil with a pH between 6.0 and 7.5. Heavy clay benefits from compost worked in before planting, and sandy soil needs more frequent watering. The plant does not need rich ground, and overly fertile beds produce tall, floppy stems that require staking.
Container growing works when the pot is at least 12 inches deep and has drainage holes. For a distinctive planting station, you can turn an old filing cabinet into a beautiful patio flower planter, filling the drawers with cleome, lantana, and trailing verbena for a vertical splash of color.
Pruning, Deadheading, and Blooming
Cleome blooms from early summer until frost, with each flower cluster opening from the bottom up. The plant is self-cleaning, so deadheading is optional; removing spent clusters keeps the bed tidy and encourages a fresh round of buds. Cut stems also last several days in water, which makes cleome a useful filler for large arrangements.
Pollinators find the nectar-rich flowers irresistible. Bees, butterflies, and hummingbirds visit throughout the day, and in fall the seed pods feed finches and other seed-eating birds. Grouping cleome in drifts of five or more plants gives pollinators a larger target and produces a stronger visual mass than single scattered specimens.
Encouraging a Second Flush
If plants grow leggy by midsummer, shear them back by one-third. They respond with bushier growth and a renewed flush of flowers within three to four weeks. Leave the final flush of seed heads in place if you want volunteers next spring, or cut them down to limit self-seeding in the same bed.
Placement decides how much these plants contribute. The tall stalks belong at the back of a border or the center of an island bed, with shorter plants staged in front. Planning a flower bed layout for stunning garden results keeps sight lines and bloom heights in order, so cleome rises behind a foreground of lower growers instead of hiding them.
Common Pests, Problems, and Seasonal Cleanup
Cleome has few serious pests, but aphids, whiteflies, and spider mites appear when plants are stressed by heat or drought. Powdery mildew shows up in humid, crowded plantings with poor air circulation, and Japanese beetles occasionally feed on the foliage in midsummer.
Aphids, Mites, and Mildew
Blast aphids and mites off with a strong stream of water, then follow up with insecticidal soap if they return. Space plants properly and avoid overhead watering to keep mildew in check. In severe cases, remove the worst foliage and improve airflow around the bed.
- Space plants 12 to 18 inches apart for air movement.
- Water at the base in the morning so leaves dry by nightfall.
- Inspect the undersides of leaves weekly during hot, dry spells.
- Remove and dispose of heavily infected plants rather than composting them.
Managing Self-Seeded Volunteers
Self-sown seedlings appear in spring wherever pods dropped the previous fall. Thin them to proper spacing or transplant the strongest volunteers to new spots. The taproot means volunteers transplant best while young, before the root grows deep and the stem becomes brittle.
In fall, ripening pods attract birds, and in spring the tender new growth can tempt digging animals. The same methods used for protecting flower bulbs from squirrels, including wire mesh, repellents, and distraction plantings, work when animals start scratching through freshly worked beds.
Cleome asks for full sun, well-drained soil, and room to grow, and it returns the favor with months of bloom. If your yard has no prepared border, a raised bed solves the drainage and soil questions in one build; follow the steps to build a raised flower garden for blooming success, then set the spider flowers against a backdrop of loose, fertile ground.