Native & adapted

Willow acacia

Acacia salicina

Narrow, evergreen Australian shade tree; place away from paving and use as an adapted—not native—canopy.

Arid adaptedEvergreenFast growingLow water

Landscape layersUpper canopy

Mature size

20–30 ft tall × 15–25 ft wide

Climate fit

Urban core · USDA 9b–10a · Valley suburbs · USDA 9a–9b · Desert outskirts · USDA 8b–9b

Special categories

ARID ADAPTED

Hardiness guidance

USDA zones 9–11; hard freezes can damage exposed growth

Before you plant

These conditions determine whether it will thrive.

Cold hardiness

Cover while young

Hardy to about 20°F once established. Young trees in their first winter are worth covering if a hard freeze is forecast.

Leaves and wood: damaged below 20°F

Heat tolerance

Takes full sun and heat

Best in full sun and handles west exposures. It goes yellow with frequent shallow watering or poor drainage, so water deep and seldom.

Sources:

amwua.org , desertmuseum.org

Right plant, right place

Will Willow acacia grow at your Arizona property?

Fast and mostly thornless, but not native. Keep it away from paving and sewer lines, expect litter and occasional root suckers, and train branch structure early.

Best regional fit: Urban core · USDA 9b–10a, Valley suburbs · USDA 9a–9b, Desert outskirts · USDA 8b–9b.

Light

Sun exposure

Full sun. Its narrow canopy suits warm side yards only when root and crown space are adequate.

Water

Irrigation

Low once established. Deep irrigation every 2–3 weeks in summer is generally sufficient.

Choose the actual plant, not only the label

Cultivars & selections

The species is usually sold without a cultivar. Confirm the botanical name because several unrelated narrow-leaved acacias are sold under similar common names.

Species form

Acacia salicina

Mature size20–30 ft tall × 15–25 ft wide

Best forNarrow evergreen screening and fast adapted shade

Often grows 2–3 ft per year with regular establishment water. Select an upright specimen with well-spaced branches and verify that it is not a similar acacia species.

Planting & stewardship

How to help Willow acacia thrive

1
Confirm the plant’s mature spread and underground conflicts before digging.
2
Place the root flare at finished grade and keep mulch away from the trunk.
3
Establish a wide, deep root zone instead of irrigating only at the trunk.
4
Observe seasonal growth, heat stress, and wildlife use before making major pruning changes.

Read the horticultural reference ↗