Tree-like monocot (palm), 12-25 m high, dense crown of fan-shaped, palmate leaves, old leaves forming "shag" below. Riverine deltas and floodplains.
General Biology. Growth form. Tree. Reproduction. Seed. Dispersal. Water, rodents, birds, mammals, contaminated mulch. Time to first flowering. 9+ years. Vegetative regeneration strategy. Does not resprout or produce root suckers. Seedbank persistence. Soil, short/medium, days - 6 years. Fire response. Fire resistant, fire removes the dead thatch material but plants are rarely killed. Fire encourages flowering and fruit production.
Notes. Highly adaptable, growing in a range of climates and soil types. Drought tolerant when fully established. Readily fruits and germinates easily. Seedling recruitment often occurs in a flush during wet years. Hybridises with W. robusta to form Washingtonia x filabusta. Can form dense thickets. Very hardy, drought and frost tolerant. Fruit allelopathically inhibits germination and growth of other species under laboratory conditions.
Additional information. Origin. South-western USA, north-western Mexico. History of use/introduction. Garden escape, widely planted as a landscape ornamental. Similar exotic species. Washingtonia robusta.
Suggested method of management and control. Hand pull seedlings and small plants. Cut older plants at base when not in fruit. Read the manufacturers' labels and material safety data sheets before using herbicides. For further information consult the Australian Pesticides and Veterinary Medicines Authority to determine the status of permits for your situation or state.
Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.