Ageratum houstonianum Mill

Last updated: 02 April 2015

Scientific Name

Ageratum houstonianum Mill.


Ageratum mexicanum Sweet [Illegitimate], Ageratum mexicanum Sims, Ageratum wendlandii Hort. ex Vilm, Ageratum wendlandii Bailly, Cacalia mentrasto Vell., Carelia houstoniana (Mill.) Kuntze. [1]

Vernacular Name

English Garden ageratum, mexican ageratum, blue billy goat weed, celestina azul, floss flower [2]
Japan Murasaki-kakko-azami, o-kakko-azami [2]
Hawaii Maile hohono, maile honohono, maile kula [2]
South Africa Tuin ageratum [2].

Geographical Distributions

Ageratum houstonianum is originating from Central America, but cultivated in tropical, subtropical and temperate regions. It is found naturalised in many warmer regions including China, India and locally in Southeast Asia (e.g. Peninsular Malaysia, Java, the Philippines, and Vietnam). [3]

This plant is locally common in fields, roadsides and waste places up to 1700 m altitude. [3]

Botanical Description

A. houstonianum is from the family of Compositae an annual erect herb where at the base it sometimes creeping and rooting and up to measures 70(-90) cm tall. [3]

The stems are clothed with patent white hairs. The leaves are subtriangular, ovate to deltoid, with a size of measuring 2-8.5(-9.5) cm x (1.5-)3-6.5(-8) cm and with cordate to truncate base. [3]

The head is 5.5-7 mm long and with 75-100-flowered. The outermost involucral bracts are with both simple hairs and shorter glandular hairs while the inner involucral bracts are gradually tapered into an acute apex. The petal is measures 2.5-3 mm long. [3]

The fruit is hairy. [3]


No documentation

Chemical Constituent

No documentation

Plant Part Used

No documentation

Traditional Use

No documentation

Preclinical Data

No documentation


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No documentation

Line drawing

Ageratum houstanium

Figure 1: The line drawing of A. houstonianum Miller.[3]


  1. The Plant List. Ver1.1. Ageratum houstonianum Mill. [homepage on the Internet]. c2013 [updated 2012 February 11; cited 2014 July 23]. Available from:
  2. Wagstaff DJ. International poisonous plants checklist: an evidence based reference. Boca Raton, FL: CRC press; 2008. p.13
  3. Rahayu SSB, Ratnasih IR, Van Der Maesen LJG. Ageratum houstonianum Miller. In: de Padua LS, Bunyapraphatsara N, Lemmens RHMJ, editors. Plant Resources of South-East Asia No. 12(1): Medicinal and poisonous plants 1. Netherlands: Backhuys Publisher; 1999. p. 92-93.