Purple willow
“For reasons that no-one can fully explain, at least one purple willow variety is now spreading explosively in Canterbury. And it is spreading by seed, something it theoretically shouldn’t be able to do.” – NZ Geographic, 2025
What does it look like?
Purple willow (Salix purpurea), is a large shrub or small tree, up to 8 m high, with grey-green to yellow-green, sometimes reddish or purplish when young. The leaves are slender, often opposite each sides of the stem towards the tips of the shoot; broadening above the middle. dark glossy green above, and bluish green below.
Why is it a problem?
“It’s gone nuts and is filling up our braided rivers at a rapid rate of knots,” says Jason Butt. “It’s frightening.” – NZ Geographic, 2025
At the time of writing (December 2025) this species was not yet included in the Canterbury Maps weed mapping tool. Nor does it appear on the Weedbusters website. However, it is included in the 2024 Department of Conservation list of 386 environmental weeds in New Zealand.
As per the above quotes, this hybrid species, which was supposed to be sterile, is rapidly invading braided rivers. ECan and river conservation groups have found it in the Hurunui, Conway Piri-tūtae-putaputa, the Waiau Toa Clarence, Ashley Rakahuri and a few other major Canterbury rivers.
See also:
Conservation activities
Weedbusters has no information as yet, however the same strategies for killing crack and grey willow are likely to be effective.
See also:
- Bioeconomy Science: Key to willow species and hybrids present in New Zealand
- NZ Geographic: Our deeply toxic relationship with willows, Issue 194 July-August 2025,