Trichostema dichotomum
blue curls
SunFull Sun – Part Shade
Overview
Trichostema dichotomum is a bushy, branched annual in the mint family, growing 8-30 inches (20-75 cm) tall with glandular, sticky-hairy stems and a sharp scent when bruised. The opposite leaves are oval to lance-shaped, 0.5-2.5 inches (1.5-6 cm) long, and untoothed. From late summer the plant opens small two-lipped flowers about 0.3 inch (8 mm) wide in blue to violet, each with four long, deeply arched blue stamens that curl well beyond the petals and give the plant its common name. Individual flowers open in the morning and drop by afternoon, with new ones following daily over many weeks. The plant grows on dry, sandy or rocky soils in open woods, clearings, old fields, and roadsides, and depends on warm-season moisture. It is drought tolerant once rooted but, as an annual, survives the winter only as seed. It self-sows on bare, open ground and reappears each year. In rich or shaded soil it grows lank and flowers less.
Native Range
Trichostema dichotomum is native to eastern North America, from southern Ontario and Maine south to Florida and west to Texas and the eastern Great Plains. It grows in dry, sandy or rocky open woods, clearings, old fields, and roadsides.Suggested Uses
Forked bluecurls is used in sandy native plantings, pollinator gardens, and meadow or restoration seedings on dry ground. It suits hot, lean, well-drained sites among grasses and other dry-land annuals. Its late-season flowers serve as a nectar source for bees on poor soils.How to Identify
Appearance
Size & Dimensions
Height8" - 2'6"
Width/Spread8" - 1'6"
Bloom Information
Flowering runs from late summer into fall, about August through October. Each blue flower opens in the morning and drops its petals by afternoon, with fresh flowers continuing daily over many weeks. Small nutlets ripen in the calyx as bloom continues up the branches.
Detailed Descriptions
Flower Description
blue to violetFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Water & Climate
Water Needs
Drought Tolerance
Drought tolerant when established
Care & Maintenance
Care Guide
Forked bluecurls grows in full sun to light shade on dry, sharply drained sandy or rocky soils, often acidic, and tolerates poor, low-fertility ground. It is drought tolerant once established and needs little summer water. As an annual it sets seed and dies with frost, leaving no perennial structure. Rich, moist, or shaded soil makes it grow lank with fewer flowers. It self-sows on bare, open ground and returns from seed each year. Sowing seed in spring after frost suits its warm-season growth.Pruning
As an annual, the plant is not pruned. Spent plants can be left to scatter seed or cleared once frost ends the season. Removing plants before seed set limits self-sowing the next year.✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
direct sow
Direct Sow Timing
spring after frost
Days to Maturity
90–120 days
Plant Spacing
10 inches