An initiative of Earthwatch Institute

  1. Desert_ash_tree_flowers_sheldon_navie Desert Ash Tree flowers by Sheldon Navie
  2. Desert_ash_tree_mature_fruit_sheldon_navie Desert Ash Tree Mature fruit by Sheldon Navie

Ash Tree

Fraxinus angustifolia


Large deciduous tree with yellow leaves in autumn, around 20m high. Leaves are 14-20cm long and comprised of leaflets. Has brown buds in winter. Many flowers in spring and fruit. 

Size: around  20m high

Leaves: 14-20cm long, usually 5-7 (or occasionally 13) leaflets, which are each 5-8cm long and 0.7-2cm wide. Serrated edges with pointed leaf tips. Bright and shiny green on upper side and dark and pale on underside. 

Flowers: Many inconspicuous flowers with no sepals or petals. Red to purple anthers (pollen-bearing part of a flower). 

Fruits/seeds: Fruits are samara (type of dry fruit that are winged to help carry the seed away via wind). Samara are in a cluster of 6-10, flattened, 3-4cm long with the seed confined to half the fruit.

What to Observe

  • First fully open single flower 
  • Full flowering (record all days)
  • End of flowering (when 95% of the flowers have faded)
  • No flowering
  • Fruits/seeds (record all days)

ClimateWatch Science Advisor

Weeds are one of the main threats to biodiversity and agriculture in Australia and under climate change will become an increasing management challenge for natural resource management.

We expect plants to start shooting and flowering earlier in the year as a result of climate change warming the Earth. They may also start appearing in new areas, as warmer temperatures enable them to live in environments that were previously too cold for them. Help scientists answer the question: "How are our animals, plants and ecosystems responding to climate change?"

When To Look

Flowering occurs in spring, which is the best time to remove this weed.

Note: ClimateWatch is looking for any changes in the timing of these events so remember to keep a lookout all year!

Where To Look

Common in ACT, VIC and SA, but can also be found in TAS, WA and NSW. 

Note: ClimateWatch is looking for any changes outside of their known ranges so remember to keep a lookout beyond these regions too!

Ash Tree (pest species) distribution map - GBIF

Ash Tree (pest species) distribution map - GBIF



Royal Botanic Gardens Victoria 2015 (

Plantnet (


  1. Search Species

  1. What Else?

    F. angustifolia subsp. Oxycarpa has grand purplish foliage in autumn whereas the Desert Ash has Yellow leaves in autumn. Both are weeds that should be removed from natural areas.

  1. Did You Know?

    Desert Ash was once a popular deciduous tree used commonly in streetscapes and gardens. It establishes in bushland and grasslands and also along stream banks and drainage lines. It out-competes native plants for moisture, light and nutrients and takes over these areas