Crack Willow Tree

Common Name: Crack Willow or Brittle Willow

Scientific Name: Salix fragilis

Native to: Europe and Western Asia. In Tasmania, Willow trees are an invasive species and are classified as a weed. 

What does it look like: The Crack Willow is a medium to large sized deciduous tree – this means that it sheds its leaves in the wintertime. It has dark grey-brown bark and bright green long leaves that grow on drooping branches. 

Why is it invasive: Willow trees are a declared weed in Tasmania because they can cause many problems within Tasmanian ecosystems. Since they love water, Willow trees grow and spread their roots along waterways (like along the Hobart Rivulet). Their roots reduce the amount of oxygen in the water, slow down the flow of the water and disturb the habitat for fish and other animals. Willow trees can also cause problems for native plants and trees when they use too much sunlight and ground space for their roots. Crack Willows are especially problematic because they can drop tree branches, which travel downstream and grow into new willow trees. 

STEM Fun Fact: In 2020, the City of Hobart begun the removal of harmful Willows on the Hobart Rivulet. They intend to continue a staged removal of the remaining willow trees to provide a safer and healthier habitat for native wildlife and plants.