Asteraceae FAMILY

Ageratum houstonianum

Edibility

0/5

Medicinal

2/5

Safety & Hazards

None known

Cultivation Details

HabitAnnual

Growth—

Tolerates temperatures down to between -5 and -10°c^[1]. Grows well in ordinary garden soil^[1]. Requires a sheltered position in full sun^[1]. Often grown as an ornamental, the plant has escaped from cultivation and become naturalised in many areas^[2]. The flowers are very attractive to butterflies^[3]. The removal of dead flowers will extend the flowering season.

Propagation

Seed - surface sow early spring in a light position in a greenhouse. The seed usually germinates in 1 - 3 weeks at 20°c^[4]. When large enough to handle, prick the seedlings out and plant them out after the last expected frosts. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-20. <temperate.theferns.info/plant/Ageratum+houstonianum>

Pollinators

Lepidoptera

References

[1]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
[2]Pacific Island Ecosystems at Risk — http://www.hear.org/pier/scientificnames/index.html ↩︎A very good website detailing weed species that have been introduced into the Pacific Islands.
[3]Butterflies and Moths in Britain and Europe. — Carter D. · Pan · 1982 · ISBN 0-330-26642-x ↩︎An excellent book on Lepidoptera, it also lists their favourite food plants.
[4]Growing from Seed. Volume 1. — Rice. G. (Editor) · Thompson and Morgan. · 1987 · ISBN - ↩︎Very readable magazine with lots of information on propagation.
[5]Manual of the Southeastern Flora. — Small J.K. · University of N. Carolina Press. · 1933 · http://www.biodiversitylibrary.org ↩︎Getting rather dated now, an immense work covering the flora of Southeastern N. America. No pictures, it is not for the casual reader. It can be downloaded from the Internet.
[6]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
[7]Plant Resources of Southeast Asia — http://proseanet.org/ ↩︎Lots of information on the uses of the plants of SE Asia.
[8]Plants and People of Nepal — Manandhar. N. P. · Timber Press. Oregon. · 2002 · ISBN 0-88192-527-6 ↩︎Excellent book, covering over 1,500 species of useful plants from Nepal together with information on the geography and peoples of Nepal. Good descriptions of the plants with terse notes on their uses.