How to Grow Cleome (Spider Flower): Planting, Spacing, Care & Bloom
Quick answer
Direct sow after last frost when soil is warm. Start indoors −8 to −6 (WI/Clemson). Footnote: Cornell lists indoor −6 to −4. Not the houseplant spider plant (Chlorophytum).
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Cleome / spider flower (Cleome hassleriana) — tender heat annual. Some types have prickles and a musky scent — handling caution, not a poison label. Not the houseplant spider plant.
Sourced from university extension guides. For dates where you live, use the ZIP planting planner.
Planting timing
Wisconsin: start indoors 6 to 8 weeks before average last frost, or seed outdoors after all danger of frost has passed; wait until soil has warmed. (Wisconsin spider flower) Clemson: direct sow after frost when soil is about 70 to 75°F; or start indoors 6 to 8 weeks before transplanting; blooms 70 to 80 days after germination. (Clemson HGIC 1196) Footnote: Cornell indoor 4 to 6 weeks before last frost. Planner: Start indoors last frost −8 to −6; Direct sow / Transplant last frost 0.
Depth and spacing
Clemson: cover ¼ inch; thin to 10–15 inches. NC: height 3–6 ft; width 1.5–2 ft; space 12 inches–3 feet.
Sun, soil and water
Full sun to light/partial shade; average well-drained; heat/humidity/drought tolerant (NC/Clemson). Avoid overwatering/overfertilizing (leggy — WI).
Care
Deadheading not required (Clemson). Self-seeds aggressively on fertile types — thin seedlings (WI). Staking usually unnecessary.
Bloom
June until frost (Clemson). About 70–80 days after germination (Clemson). Good cut flower (NC).
Pests and diseases
NC: spider mites, aphids, flea beetles, caterpillars; rust, powdery mildew. Clemson: aphids, spider mites, whiteflies; mildew/rust in hot humid climates — space for air; remove dead plants after frost. Soft-bodied pests: insecticidal soap/oil as labeled.
Related: ZIP planner · organic pest control
Frequently asked questions
When do I plant cleome / spider flower?
Direct sow after last frost. Start indoors −8 to −6.
Same as spider plant (Chlorophytum)?
No — garden spider flower is Cleome, not the houseplant.
Days to bloom?
About 70–80 days after germination (Clemson).
Sources
- University of Wisconsin–Madison Extension: Wisconsin spider flower
- Clemson Cooperative Extension: Clemson HGIC 1196