Floridata Plant Encyclopedia

A Floridata Plant Profile 532 Ageratum houstonianum

Common Names: ageratum, flossflower Family: Asteraceae (aster/daisy Family)

blue ageratum
A true blue ageratum cultivar.
flossflower is perfect for low borders and edging.
Lavender and pink flossflower spill attractively onto a brick walkway.
blue ageratum
This ageratum actually has blue flowers but they appear as lavender when captured on photographic film (this is known to photographers as the 'ageratum effect').


The flossflower species is an annual that grows to a height of over 2 ft (0.6 m), has blue flowers, and tends to become a pest as it liberally reseeds itself all over the garden. The flossflowers that you'll want for the garden, however, are chosen from the wide assortment of selected varieties offered by nurseries and garden centers. These all tend to be more compact and better behaved than the basic species. These varieties form shapely mounds from 6-12 in (2.4-4.8 cm) in height and produce generous quantities of soft fuzzy flowers arranged in clusters.

Ageratum is typically seen in colors ranging from purple to blue to lavender and pink. A white flowering variety is also occasionally encountered. Leaves are oval to heart shaped and up to 4 in (10 cm) in length although for most popular varieties they are usually half that.


Ageratum houstonianum is native to an area that stretches from southern Mexico to Guatemala on the Pacific coast and eastward to Belize on the Caribbean Sea.


Light: Likes bright sun. In Florida and other hot areas, ageratum looks best if grown in part shade. Moisture: Needs supplemental watering during dry periods. Hardiness: USDA Zones 5 - 10. The party is over when frost strikes this tender annual. Propagation: Seedlings dislike being disturbed, so plant the small seeds indoors in peat pots for transplanting outdoors after danger of frost has passed. Most gardeners prefer to purchase cell packs of young plants. These are inexpensive and are universally available from nurseries, hardware and discount stores.
a bed of ageratum
Flossflower is famous for creating durable summertime flower beds.


Flossflower is perfect for contributing bulk to live container arrangements. Use it in borders and edging. Mass blue ageratum in beds with yellow marigolds for a study in complementary colors or with pink begonias to create a soft pastel carpet.


Ageratum grows quickly to form compact mounds of fresh looking foliage that are covered with blossoms for nearly all summer and into fall. It is available in several shades of blue that provide a nice contrast to other common bedding materials.

Jack Scheper 01/22/99; updated sc 11/27/1999, 06/09/01, 05/15/03, 09/14/03, 2/11/05, 4/6/16

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Ageratum species profiled on Floridata:

Ageratum houstonianum

( ageratum, flossflower )

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