Priority: - Control
Identification and Reproduction
This plant is a semi deciduous shrub. Blooming periods are around the end of July to August and they can have a wide range of mauve, purple, pink, and flat-night flowers.
They are known to have a honey fragrance, hence why people cultivate these plants for pollinators.
Leaf arrangement is opposite.
Plant height around two to four meters high and may extend over an area of 2-3 m2.
Seeds are mainly dispersed by wind during dry days, but they can also spread by water-dispersal (flowing through lakes and rivers). Cars are also capable to produce enough air movement for wind dispersal.
Butterfly bush can produce asexually from plant parts.
Habitat & Ecology
Disturbed areas ranging from light shade to full sun.
Outcompetes native species and may alter riparian habitats.
Flowers may feed butterflies, but caterpillars will not feed on the leaves. Therefore this plant cannot support the whole life cycle of butterflies, leaving caterpillars lacking a food source if other plants are not in the area.
Mechanical: Remove seed capsule before they ripen.
Remove larger bushes by cutting the plant at the base.
Dig up the stump if possible, or cover it with a thick plastic bag or mulch to prevent regeneration.
Remove new shoots until the rootstock dies, and do not leave stems on the ground, or they may root.
Chemical: Cut plants should be treated with glyphosate.
Alternative: Sterile versions (not capable of reproducing) of this plant are available.
This management factsheet is from the US, so herbicide regulations and use in Canada may differ. This is here as an additional source of information. Always follow the product label of the chemical product you are using!