How to Grow Cleome (Spider Flower): Planting & Care

Cleome is one of the easiest tall annuals you can grow from seed, and once you have it, you tend to have it forever. Direct-sow seed in full sun after your last frost, give plants 18 to 24 inches of room, water them until they’re established, and then mostly leave them alone. They’ll climb to 3 to 5 feet by midsummer and throw airy, spidery pink, white, and purple flowers from June until hard frost. The plant is heat-tolerant, drought-tolerant once rooted, deer-resistant, and a magnet for bees, butterflies, and hummingbirds. The one thing you do need to know going in: old-fashioned Cleome hassleriana reseeds aggressively, so you’re either committing to a self-renewing patch or you’re choosing a sterile hybrid that stays put.

Plant Overview and Varieties

Cleome, commonly called spider flower or spider plant (not to be confused with the houseplant of the same nickname), is a warm-season annual grown for its tall, see-through flower clusters. The blooms open from the bottom up over a long stem, each flower trailing long, whisker-like stamens and slender seed pods that stick out at angles, which is exactly where the “spider” name comes from. Individual plants form a single strong stalk that branches near the top, topping out anywhere from 3 to 5 feet depending on variety, soil, and water.

The classic species is Cleome hassleriana, sold under named seed strains like ‘Queen’ (in cherry, rose, violet, and white), ‘Sparkler’, and ‘Helen Campbell’ (a pure white). These are the workhorses: cheap from seed, vigorous, and prolific self-sowers. Their downside is that mature stems carry small thorns at the leaf bases, the foliage is sticky to the touch, and the plant gives off a sharp, musky, somewhat skunky scent when you brush against it or handle it on a hot day. Most gardeners stop noticing it; some never make peace with it.

The newer answer to all three complaints is the ‘Senorita Rosalita’ (lavender-pink) and ‘Senorita Blanca’ (soft white) series of hybrids. These are thornless, far less odorous, more compact at roughly 2 to 4 feet, and crucially they are sterile, so they bloom non-stop without setting seed and never reseed into a thicket. You buy them as plants rather than seed, but for a tidy border or a container you don’t want to police, they’re worth it. If you love the cottage look and the volunteers, stick with the species; if you want control, go hybrid.

Climate and Sun Requirements

Cleome is grown as an annual everywhere in the United States, which means it doesn’t much care about your USDA hardiness zone for survival; it lives one season and dies at frost. What it cares about is heat and light. It thrives across roughly USDA zones 2 through 11 as a summer annual, and it performs best in the long, hot summers of zones 5 through 9. Cool coastal summers will still produce flowers, just shorter, slower plants.

Give it full sun, meaning a minimum of 6 hours of direct light and ideally 8 or more. In too much shade, stems stretch, lean, and flop, flowering thins out, and the plant becomes far more prone to powdery mildew. Cleome genuinely shrugs off summer heat that wilts other annuals, and once its deep taproot is down it tolerates drought well. It’s also unfussy about soil: average, well-drained ground is fine, and overly rich soil actually produces lush, weak, floppy growth at the expense of flowers. Slightly lean soil with good drainage gives you sturdier, more self-supporting plants.

When and Where to Plant

Timing is simple: wait until all danger of frost has passed and the soil has warmed to at least 60°F before sowing or transplanting outdoors. For most of the country that lands somewhere between late April and early June. Cleome seed will not germinate well in cold soil, and seedlings sulk or rot if you rush them out in a chilly, wet spring. If you’re starting seed indoors to get a head start, sow about 4 to 6 weeks before your last expected frost date.

For placement, lean into the height. Cleome belongs at the back of a sunny border, along a fence line, against a wall, or in the middle of an island bed where 4-foot plants won’t shade out everything in front of them. It reads as a fine, airy screen rather than a solid mass, so it pairs beautifully in front of taller structures and behind mid-height bloomers. It’s a natural in a cottage garden, a cutting garden row, or a dedicated pollinator patch. The shorter ‘Senorita’ hybrids work in large containers and toward the middle of a bed. Avoid planting cleome right beside a patio seating area or a doorway if the species’ scent bothers you, since that’s where you’ll handle it most.

Sowing Seed and Germination (Cold Stratification)

Cleome seed germinates best with a swing between cold and warm, which mimics the winter-then-spring cycle the seed expects in nature. A period of cold stratification noticeably improves both the percentage of seeds that sprout and how evenly they come up. The easiest method: mix the seed with a little barely-damp sand or vermiculite in a zip bag and refrigerate it for 1 to 2 weeks before sowing. Some gardeners skip the bag and simply sow seed outdoors in late fall or even on top of snow, letting winter do the chilling, which is also why fall-dropped seed comes up so reliably the next spring.

Direct sowing

To direct-sow, rake the bed smooth, scatter or press seed onto the surface, and cover it with no more than 1/8 inch of soil. Cleome needs light and fluctuating day-night temperatures to break dormancy, so don’t bury it. Keep the surface evenly moist until germination, which takes about 10 to 14 days in warm soil. Thin seedlings to final spacing once they have a couple of true leaves.

Starting indoors

If you start indoors, stratify the seed first, then sow into cells, barely covering it. Provide bright light and warmth of about 70 to 75°F, and consider a daily temperature drop at night to trigger sprouting. Cleome resents root disturbance, so use deep cells or peat pots and transplant before the taproot circles. Harden seedlings off over a week before they go outside.

Spacing and Transplanting

Space cleome plants 18 to 24 inches apart in every direction. It’s tempting to crowd them because young seedlings look small and lonely, but these plants get big and bushy near the top, and tight spacing leads to poor air circulation, powdery mildew, and tall, leggy, leaning stems that lose their lower leaves. Generous spacing gives you fuller, sturdier plants that stand on their own.

When transplanting, handle the root ball gently and set plants at the same depth they grew in the pot. Because cleome forms a taproot, the sooner you get a young plant into the ground the better it establishes; rootbound transplants languish. Water in well at transplant time and keep the soil consistently moist for the first two to three weeks while roots take hold. After that, the plant is largely on its own. The shorter hybrid series can sit a bit closer, around 12 to 18 inches, since they branch lower and stay more compact. If you’re growing for cut flowers in rows, 18 inches between plants with 24 to 36 inches between rows gives you working room and straight stems.

Watering and Feeding

Newly planted cleome needs regular water to establish, so give it about an inch a week through the first month, soaking deeply rather than sprinkling lightly. Once it’s rooted, cleome is genuinely drought-tolerant and prefers to dry out between waterings rather than sit in constantly wet ground. Deep, infrequent watering encourages the taproot to go down and makes the plant more self-reliant and more upright. Overwatering, like overly rich soil, produces soft, floppy growth.

Feeding should be light. Cleome flowers more freely in average to lean soil, and heavy nitrogen pushes leafy, weak stems with fewer blooms. If your soil is poor, work in a modest amount of compost at planting and that’s usually enough for the whole season. If you feel the need to feed container plants, use a diluted balanced fertilizer once a month at most. Skip the high-nitrogen lawn-style feeds entirely. A 2-inch layer of mulch helps hold soil moisture, keeps roots cooler, and cuts down on weeding, but keep it pulled back an inch or so from the stem base.

Staking, Support, and Deadheading

Well-grown cleome in lean soil and full sun usually stands on its own, but a tall, lush plant in rich ground or a windy, exposed spot may lean or snap. The best support is preventive: grow plants in groups so they lean on each other, and consider pinching the growing tip when seedlings reach 8 to 12 inches to encourage branching and a bushier, lower habit. In a cutting bed, a single layer of horizontal netting stretched at about knee height, which the plants grow up through, keeps stems vertical and straight. For one or two individual specimens, a single bamboo stake and a loose tie is plenty.

Deadheading is optional but useful. Removing spent flower spikes before they set those long seed pods keeps the plant tidy, pushes more bloom, and is the single most effective way to cut down on next year’s self-sown seedlings. If you want the volunteers, leave the pods to ripen and drop. If you don’t, snip the spikes as they fade. With the sterile ‘Senorita’ hybrids this is moot, since they don’t set seed and bloom continuously without any deadheading at all.

Managing Self-Seeding

This is the trait that defines old-fashioned cleome. Cleome hassleriana sets enormous quantities of seed in those slender pods, the pods split and fling seed several feet, and that seed overwinters in the soil and sprouts the following spring after natural cold stratification. The result is a patch that renews itself year after year with no effort from you, which is wonderful in a cottage garden or naturalized bed and a nuisance in a tightly managed border. Volunteers won’t necessarily come up exactly where you want them, and a single planting can colonize a surprising area within a couple of seasons.

To control it, deadhead before pods mature, and in spring simply hoe or pull the seedlings you don’t want while they’re young; they’re easy to identify and easy to yank. You can also transplant volunteers to where you’d prefer them when they’re still small. To eliminate reseeding entirely, grow the sterile hybrids. Cleome reseeds enthusiastically, but it isn’t a deep-rooted invasive thug like some self-sowers, so even in the worst case a season of diligent pulling clears it out. If you enjoy the look of a self-renewing meadow-style planting, cleome pairs naturally with other reseeding annuals; some gardeners let it mingle with flowering tobacco (nicotiana) for a tall, fragrant, dusk-friendly back border.

Pests and Common Problems

Cleome is refreshingly trouble-free. Deer and rabbits generally leave it alone thanks to the strong scent and, on the species, the thorny stems, which makes it a reliable choice for properties with browsing pressure. The most common issue is powdery mildew, a white dusty coating on leaves, which shows up when plants are crowded, shaded, or stressed by drought-then-flood cycles. Prevent it with full sun, proper 18-to-24-inch spacing, and good airflow; mildew rarely kills the plant but it makes lower foliage ugly.

Aphids may cluster on tender new growth and flower stems, especially on stressed plants; a hard spray of water or an insecticidal soap handles them, and the many beneficial insects cleome attracts tend to keep them in check anyway. Spider mites can appear in hot, dry, dusty conditions and are managed by hosing plants down and keeping them watered enough to avoid drought stress. Leaf yellowing usually signals overwatering or soggy soil rather than a disease, so check drainage first. Beyond that, flopping is the main complaint, and it traces back to too-rich soil, too much water, too little sun, or too little space rather than any pest. For more tough, heat-loving, low-care annuals to plant alongside it, browse our Plants & Flowers guides.

Cleome as a Cut Flower

Cleome earns a spot in the cutting garden for its height, its airy texture, and a long, productive bloom window from early summer to frost. Cut stems in the cool of the morning when the lower flowers on the spike have opened but the top is still in bud; the buds continue opening in the vase. Strip the lower leaves, get the stems into water immediately, and expect a vase life of roughly 5 to 8 days. Wear gloves when cutting the species, since the stems are sticky and lightly thorny and the cut foliage carries that musky scent more strongly indoors.

For arrangements, cleome plays the role of a tall, see-through accent rather than a focal bloom; it adds movement and a hazy, romantic quality behind more solid flowers. It mixes well with zinnias, cosmos, and other summer annuals, and for a bold, high-impact combination it stands up beautifully next to the fiery orange daisies of Mexican sunflower, which loves the same heat and full sun. Regular cutting, like deadheading, only encourages the plant to produce more stems.