Annual flower
Ageratum plant profile
Ageratum houstonianum
An annual flower for full sun.
Last updated .
When to plant
When to plant Ageratum
Start seeds indoors
10 weeks before your last spring frost to 8 weeks before your last spring frost
Transplant outdoors
at your last spring frost to 2 weeks after your last spring frost
Growing conditions
- Sun
- Full sun
- Lifecycle
- Annual
- Spacing
- 6 to 8 in apart
Common problems
Watch for these
Evidence trail
Evidence behind this profile
Original extension and institutional publications behind the planting, care, and safety facts on this page.
- Ageratum, Ageratum houstonianum
University of Wisconsin-Madison Division of Extension (Wisconsin Horticulture). Supports indoor seed-starting timing (direct) and outdoor transplant timing (normalized). Checked 2026-06-18.