Ageratum (Flossflower) in Zone 10a & 10b

Ageratum houstonianum

When to plant ageratum (flossflower) in zone 10b

Zones 10a and 10b 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	Dec 12–Dec 19
Direct sow / transplant outside	Feb 6–Feb 13
Estimated bloom	Apr 22–Apr 29 (~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 10's season

Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. 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

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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 10b 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 10b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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