|Botanical Name||Ageratina adenophora|
DescriptionStems chocolate-brown, woody, may have numerous galls 10-20mm long formed. Flowers: White terminally compound clusters spring and summer. Dark green leaves, opposite, lanceolate, lobed, toothed. Wind-borne seed dispersal (100,000/plant), or root fragments. Erect herb to subshrub, 1-3 m tall. Stems densely clothed in stalked glandular hairs; sometimes purple. Leaves opposite and diamond shaped, to around 100 mm long. Flowers white, Aug-Dec-(Mar). Can be distinguished from mist flower by the leaf shape and stalked glandular hairs without stripes.
Where is it found?Shrublands and disturbed sites, stream sides, margins and light gaps of forest, coastal and inshore islands, open rocklands, sand dune systems, intertidal rivers and estuaries, freshwater wetlands, coastal forest, disturbed forest sites and alluvial flats, roadsides, gravel pits and quarries, exotic plantations, rough pasture.
Why is it a problem?Capacity to infest a large range of plant communities with moderate to high light intensity ranging from dry shrublands to wet stream sides. Open-dense thickets formed from spent flowering stems falling flat and overlying one another. Capable of flattening and pinning down seedlings. Regeneration of new seedlings often difficult under such thickets. This plant may impair successional processes of developing forests.
How does it spread?Infestation sites and dispersal routes are often roadsides, track margins, wasteland, grazed or disturbed forest. Seed is spread by wind, water and probably road mowers.
How do I get rid of it?
Dig out/rotary slash, depending on size of infestation.
Allow sprayed vegetation to rot. Compost or burn dug out plants.
|Mexican devil gall fly was imported to New Zealand in 1958.|
|Recommended Approach||Dig out small infestations. Tackle control operations at a time when the plant is in flower but before it sets seed (Aug-Jan). Where possible weaken the population growth by slashing or light spraying until native vegetation takes over and outshades the weed.|
This plant is prohibited from propagation, sale and distribution within the Bay of Plenty Region!