Ageratum (Flossflower) in Zone 2a & 2b
Ageratum houstonianum
When to plant ageratum (flossflower) in zone 2b
Zones 2a and 2b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. Ageratum (Flossflower) needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Apr 1–Apr 8 |
|---|---|
| Direct sow / transplant outside | May 27–Jun 3 |
| Estimated bloom | Aug 10–Aug 17 (~75 days after transplanting) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Ageratum, also known as flossflower or blue mink, is a fuzzy-textured filler flower that's a classic choice for the back of a bed or a mass planting, needing no pinching or staking along the way.
How ageratum (flossflower) fits zone 2's season
Zone 2b's frost-free window runs about 104 days, from May 20 to September 1. Ageratum (Flossflower) needs about 75 days from transplant to first harvest.
Good companions
No standout companions recorded yet for Ageratum (Flossflower).
Where to buy ageratum seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing ageratum (flossflower)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 2b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Ageratum (Flossflower) in USDA zone 2b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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