ageratum [Gr.,=unaging], any plant of the genus Ageratum, tropical American annuals of the family Asteraceae (aster family). The commonly cultivated species is the Mexican A. houstonianum, with thick terminal clusters of blue flowers. The similar mistflower, a Eupatorium (see boneset), is a perennial sometimes called hardy ageratum. Ageratum is classified in the division Magnoliophyta, class Magnoliopsida, order Asterales, family Asteraceae.

Any plant of the genus Ageratum, of the composite family, native to tropical South America. Ageratum have toothed, oval leaves that are opposite each other on the stem; compact clusters of blue, pink, lilac, or white flowers; and small, dry fruits. Dwarf varieties are used as edging plants. Some ageratum are variously known as flossflower and pussyfoot.

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Ageratum (A-gé-ra-tum), known as Whiteweed is a genus of 40 to 60 tropical American herbs, annuals and perennials from the Sunflower family Asteraceae, tribe Eupatorieae.

They form tussocks or small hills. They grow to a height of 75 cm. The opposite leaves are cordate or oval, hairy or tomentose. The margins are slightly toothed or serrate. The leaves form compact clusters.

The fluffy flowers are lavender-blue, pink, lilac, or white; and spread in small compound umbels.

They give small, dry fruits.

Ageratums as garden plants

They are grown for their flowers, especially the Flossflower (Ageratum houstonianum). Many are useful for bedding and bordering or in rock gardens.

Most common ageratums, "Hawaii" for example, are a short 6-8 inches when full grown. Tall ageratum are also available in seed catalogues, but rarely in retail stores. They are about 18 inches in height with blue flowers. There is also a medium height snowcapped variety, white top on blue flowers. The blues are most popular and common, but colors also include violet, pink and white. Their size and color makes Ageratum good candidates for rock gardens, flower beds, and containers.

Ageratum grow well in the sun or partial shade, from early summer to first frost. They are quite easy to grow, producing a profusion of fluffy flowers all season long. They are excellent for beginner gardeners.

Species

• Ageratum arsenei
• Ageratum candidum
• Ageratum chortianum
• Ageratum connatifolius
• Ageratum conyzoides: Billy-Goatweed, Tropical Whiteweed, Mexican Ageratum
• Ageratum corymbosum: Flattop Whiteweed, Butterfly Mist
• Ageratum corymbosum f. album
• Ageratum corymbosum f. euryphyllum
• Ageratum corymbosum var. jaliscense
• Ageratum corymbosum f. lactiflorum
• Ageratum corymbosum var. longipetiolatum
• Ageratum corymbosum var. subsetiferum
• Ageratum elassocarpum
• Ageratum ellepticum
• Ageratum gaumeri
• Ageratum guatemalense
• Ageratum heterolepis
• Ageratum hondurense
• Ageratum houstonianum : Bluemink, Flossflower, Garden Ageratum, Blueweed).
• Ageratum houstonianum var. angustatum
• Ageratum houstonianum f. isochroum
• Ageratum houstonianum f. luteum
• Ageratum houstonianum var. muticescens
• Ageratum houstonianum f. niveum
• Ageratum houstonianum f. normale
• Ageratum houstonianum var. typicum
• Ageratum houstonianum f. versicolor
• Ageratum iltisii
• Ageratum latifolium var. galapageium
• Ageratum littorale : Cape Sable Whiteweed
• Ageratum littorale f. album
• Ageratum littorale var. hondurense
• Ageratum littorale f. setigerum
• Ageratum lucidum
• Ageratum lundellii
• Ageratum maritimum
• Ageratum maritimum f. calvum
• Ageratum meridensis
• Ageratum mexicanum var. majus
• Ageratum molinae
• Ageratum munaense
• Ageratum nelsonii
• Ageratum oliveri
• Ageratum peckii
• Ageratum perplexans
• Ageratum platypodum
• Ageratum radicans
• Ageratum reedii
• Ageratum rhytidophyllum
• Ageratum riparium
• Ageratum rugosum
• Ageratum serratum
• Ageratum sordidum
• Ageratum stachyofolium
• Ageratum standleyi
• Ageratum tehuacanum
• Ageratum tomentosum
• Ageratum viscosum
• Ageratum wendlandii
• Ageratum wrightii

References