When to plant Cleome (Spider Flower)
Computed from land-grant Extension planting-window rules (cited below), localized to real ZIP-level median frost dates, not a single national guess. These are national-generic rules by hardiness class; individual state Extension offices layer their own regional adjustment on top (earlier in the Deep South, later in the Upper Midwest). Enter your ZIP for your own dates, or read the four representative locations below.
Planting windows and crop timing here are computed from USDA/NOAA climate data and the university extension sources cited below, not a site visit or soil test. Treat this as a starting point: local conditions vary, and a local nursery or extension office can advise on your exact site. See our full Disclaimer.
Representative timing, by climate band
When to plant Cleome (Spider Flower) in four US climates
Each column is the most nursery-dense location in our directory within that USDA zone band, computed from that location's own real median frost dates, not a made-up example.
| Stage |
Zones 1-5 (cold winters)
Fort Plain, NY |
Zones 6-7 (temperate)
McMinnville, TN |
Zones 8-9 (warm)
Apopka, FL |
Zones 10-13 (hot, frost rare or absent)
Loxahatchee, FL |
|---|---|---|---|---|
| Start seed indoors | Mar 11–Mar 25 | Feb 10–Feb 24 | Dec 30–Jan 13 | – |
| Direct-sow outside | May 6–May 20 | Apr 7–Apr 21 | Feb 24–Mar 10 | – |
| Transplant outside | May 6–May 20 | Apr 7–Apr 21 | Feb 24–Mar 10 | – |
| Fall planting | Not available | Not available | Not available | – |
| Expected harvest | Jul 15–Aug 8 | Jun 16–Jul 10 | May 5–May 29 | – |
Zones 10-13 (hot, frost rare or absent) (Loxahatchee, FL): Frost is rare here (about 359 frost-free days a year); most years see little or no hard freeze. This is a tender crop. In climates like this one, tender and very-tender crops typically go in before the hottest months arrive, not on a frost-relative schedule.
Sources split on cleome's frost tolerance, and this page publishes the more specific one. Clemson Cooperative Extension's dedicated Cleome (Spider Flower) factsheet (HGIC 1196) calls for direct-sowing only "after the fear of frost has passed," with soil at 70 to 75°F, and blooms 70 to 80 days after germination. NC State Extension's Growing Annual Flowers guide instead lists cleome among half-hardy annuals seeded outdoors in early spring, without requiring high soil temperatures.
Missouri Botanical Garden's Gardening with Annuals factsheet sides with Clemson, placing cleome in its Summer (tender) Annuals table and noting it resents transplanting. This page classifies cleome tender and uses Clemson's bloom window and soil-temperature figure, on the strength of that factsheet's direct, cultivar-specific detail against NC State's more general seasonal listing.
Because it resents transplanting, cleome is bought as seed rather than as a started plug.
Frost hardiness
Tender. Damaged or killed by frost. Plant after the last frost date.
Minimum soil temperature
70°F
For direct sowing/germination, where an Extension source stated it.
Days to maturity
70–80
Sourcing notes
DISAGREEMENT: NC State Extension's Growing Annual Flowers publication (accessed via search snippet; direct fetch of content.ces.ncsu.edu/growing-annual-flowers returned HTTP 403) lists cleome among half-hardy annuals seeded outdoors in early spring, not requiring high soil temperatures. Clemson's dedicated Cleome/Spider Flower factsheet (HGIC 1196) is far more specific and contradicts this: it calls for direct-sowing only "after the fear of frost has passed" with soil at 70-75F, blooming 70-80 days after germination -- squarely tender-annual timing. Missouri Botanical Garden also places cleome in its Summer (tender) Annuals table, noting it "resents transplanting." Classified tender per the more detailed, directly-verified Clemson factsheet; bloom window (70-80 days) and min soil temp (70F) are both sourced from it.
Related crops
Growing zones for this crop
Nurseries near these locations
See everything with an open window this month →
Sources
- Clemson Cooperative Extension Home & Garden Information Center, Cleome or Spider Flower (HGIC 1196) (accessed 2026-08-04)
- Missouri Botanical Garden (Kemper Center for Home Gardening / gardeninghelp.org), Gardening with Annuals (accessed 2026-08-04)
- NC State Extension Publications, Growing Annual Flowers (accessed 2026-08-04)