Weed Identification

Australia > > Black Willow

Black Willow

Salix nigra

THIS PLANT HAS BEEN DECLARED A WEED OF NATIONAL SIGNIFICANCE

Family: Salicaceae.

Form: Tree

Origin: Native to east and central North America.

Flowers/Seedhead: Flowers: Plants male or female. Flower spikes are called catkins. Male catkins yellow, female catkins green. Catkins appear with leaves in spring.

Description: Deciduous, rapidly-growing tree to about 20 m tall with one, or less often up to 4, trunks.

Distinguishing features: Distinguished by its non-drooping habit, twigs shiny and red-brown when exposed to sun, thin leaves that are almost equally green on both sides and deeply fissured grey bark on stems over 10 cm in diameter.

Dispersal: Seed, and to a lesser extent pieces.

Confused With: Other Salix species, see taxonomic text for detailed distinguishing features.


Bark, leaves & male catkin (top)
female catkin (bottom)

Notes: Introduced to Australia for soil stabilisation in 1962. Male and female trees common. Viable seeds are freely produced. Major invasive woody weed of streams and stream banks. Like Grey Sallow (Salix cinerea), Black Willow has the potential to be a major invader of wetlands. Early identification essential. May hybridise with other Salix species. In its native range it is a dominant tree, forming large stands.

References:

    Willow Identification for River Management in Australia. K. Cremer, 1995, page 8. Willows Along Victorian Waterways. A. Ladson et al., 1997, page 26. Flora of NSW. G. Harden and L. Murray (eds), Supplement to Vol. 1, 2000, page 6167.

Web References: Search Australian web sites for further information on this weed.


Tree with blackish-brown
branches

Female catkins & leaves

Female catkin

This weed has been included in the WEEDeck field guide as card T04

More information about WEEDeck is available from Sainty & Associates Pty. Ltd.

 

Australia > > Black Willow

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