Crack willow is a deciduous tree that grows to 25 m. This tree has spreading rather than hanging branches with rough and fissured bark. Root suckers and rootlets are bright-red when in or near water. Shoots and leaves are silky when young but become hairless as they mature. Leaves are narrow lance-shaped with tiny serrations. Undersides of leaves are pale, and the upper surface is shiny, green and often covered with bright-red galls. Narrow downward-curving catkins (40-75 mm long) appear from September to October. As there are only male plants in New Zealand, no fruit is formed unless hybridised with other species such as golden willow. Spread is by stem fragments carried by water movement which readily produce new plants.
This plant replaces native species in wetlands, and forms vast dense stands and thickets. It causes blockages, flooding and structural changes in waterways.
What to do
Contact your regional council to determine the status of this species and responsibility for control and/or advice on control.
Page last updated: 22 October 2008