Ageratum (Flossflower) in Zone 6a & 6b
Ageratum houstonianum
When to plant ageratum (flossflower) in zone 6b
Zones 6a and 6b 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 | Mar 7–Mar 14 |
|---|---|
| Direct sow / transplant outside | May 2–May 9 |
| Estimated bloom | Jul 16–Jul 23 (~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 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. 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 6b 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 6b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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