How to grow Flossflower

Ageratum houstonianum

Full Sun
OR
Partial Sun
Medium

Harden off young plants before establishing in their final flowering position. Space out to 15 cm to for a low border. Keep moist and weed free.
Pinch out the growing tip to encourage busher plants.

Growing Flossflower from seed

Stat seds indoor very early spring, in trays of compost.
Sow thinly and do not cover seeds with compost. Firm gently and keep moist. Cover the tray with a sheet of glass or perspex and keep at 20 to 25C
Remove the cover when the seedlings germinate, and when large enough to handle transplant to 5cm apart in trays. Grow on at 15C.

By our calculations*, you should look at sowing Flossflower about 49 days before your last frost date .

Transplanting Flossflower

Harden off the seedlings, and plant out when all danger of frost has past, into the final flowering position
Plant 15cm apart
Keep moist and weed free

As Flossflower is tender, ensure temperatures are mild enough to plant out (around 15°C / 59°F as a guideline) - wait until after your last frost date to be on the safe side.

Seed Saving Flossflower

Collect seeds into a paper bag and store in a cool dry place. If annuals are allowed to run to seed, they do not continue to flower, so only allow seed heads to develop towards the end of the flowering season

How long does Flossflower take to grow?

These estimates for how long Flossflower takes to sprout, grow and harvest are from real observations from real gardeners, right around the world.

Days to Germination How long does it take Flossflower to germinate?: 21 days
Average 21 days | Min days | Max days (0)
Days to Transplant How long until I can plant out Flossflower?: + days
Average days | Min days | Max days (0)
Days to Maturity How long until Flossflower is ready for harvest / bloom?: + 100 days
Average 100 days | Min days | Max days (0)
Total Growing Days How long does it take to grow Flossflower?: = days

When should I plant Flossflower?

Our when to plant Flossflower estimates are relative to your last frost date.

When to sow The number of days to sow Flossflower before or after your last frost date.: 49 days before Last Frost Date

Flossflower Folklore & Trivia

Agerantum houstonianum produces a methoprene-like compound which interferes with the normal function of the corpus allatum, the organ responsible for secreting juvenile hormone in insects. This chemical triggers the next molting cycle to prematurely develop adult structures and can render most insects sterile, if ingested in large enough quantities.¹

Other names for Flossflower

Bluemink, Flossflower, blueweed, Ageratum

Ageratum houstonianum Mill.

Footnotes

¹ en.wikipedia.org/wiki/Ageratum_houstonianum