Actual size and flowering may vary slightly based on season.
Mulga Acacia
Mulga Acacia is a small evergreen tree from the dry interior of Australia, grown here for its silvery gray-green leaves and dense, upright shape. It usually reaches about 15 to 20 feet tall and 10 to 15 feet wide, and it grows slowly. People plant it as a year-round screen, a patio or accent tree, or near the pool, since it has no thorns and drops little litter. It takes full sun and reflected heat on low water once it is rooted in.
Best for: a year-round evergreen screen, a small patio or accent tree, planting near the pool, and hot spots with full sun and reflected heat.
Mulga keeps its dense, silvery gray-green leaves all year, so a row of them makes a screen or windbreak. Plant them about 12 to 15 feet apart for a screen, or up to 20 feet apart in a looser group. It grows slowly, so a screen takes a few years to fill in.
It has no thorns and drops little litter, which is why people plant it beside patios and pools. At about 15 to 20 feet tall and 10 to 15 feet wide, it fits smaller yards and tight spaces. Water it at the edge of the canopy, not at the trunk.
Mulga takes full sun and reflected heat, which is why it is also planted along streets, medians and parking lots. Once rooted, soak it 2 to 3 feet deep at the canopy edge about every 2 to 3 weeks in summer and about once a month in winter.
It does not handle soggy soil, so keep it out of lawns and away from thirsty plants, where poor drainage can rot the roots. It grows slowly, so it is not a quick shade tree. The wood is stiff and brittle, so prune lightly and shape it while it is young.
- Screen row12-15 ft apart
- Small group15-20 ft apart
For the first two weeks, water a new tree every 1 to 2 days in summer, or every 3 to 4 days in cooler months. Ease to about weekly in summer by the second month, and keep up deep, regular soaks for its first 3 years. Once rooted, soak it 2 to 3 feet deep at the canopy edge about every 2 to 3 weeks in summer and about once a month in winter.
Take off the nursery stake at planting, and stake only if the tree cannot stand on its own or sits in a windy spot. Use two stakes outside the root ball and soft, wide ties that let the trunk sway. Remove them after about a year. Tree acacias grow top-heavy, so many need stakes while young.
It needs little pruning, so shape it and raise the canopy slowly as it grows. Never take more than a quarter of the leaves in a year, and do not strip the inside branches bare. Finish any thinning before monsoon season starts in mid-June.
Too much water or soil that stays wet can rot the roots and turn the leaves yellow. Water deeply, then let the soil dry out before the next soak.
Drainage test first. Dig the hole and fill it with water. If water is still sitting in the hole a day later, you likely hit caliche, clay or hard soil, so fix the drainage before planting. If it drains very fast, the soil is sandy. Standing water around roots is a common reason new plants fail.
Weed cloth. Cut it away from the planting hole and where the roots will spread. Remove any plastic sheeting completely, since it keeps water and air out of the soil.
Rock or decomposed granite with no soil underneath. Bring in soil close in texture to your native soil, mix it with the soil below, and build up enough depth for roots before planting.
If you can break through. Use a breaker bar, pick, or jackhammer. Dig through the caliche and break out the solid chunks. Backfill with the soil you dug out, with no compost or manure in the hole. Confirm drainage before planting.
If you cannot break through. Dig narrow holes through the hard layer beside the root ball, not under it, and refill them with the same soil, not gravel. If it still will not drain, plant on a low mound of the same soil.
Root ball. Check the outside edges for any roots circling around. Loosen or cut those so they grow outward. Do not break up the center of the root ball.
Depth. The top of the root ball should sit at or just slightly above the surrounding soil level. Planting too deep can lead to rot and kill the plant.
Drip emitters. At planting, put the emitters on the root ball, on different sides of the plant. After about 2 months, move them to the outer edge of the root ball. Over the first year, add emitters farther out toward the edge of the branches as roots grow. Once a plant is rooted, never water only at the trunk.
How big does Mulga Acacia get?
Usually about 15 to 20 feet tall and 10 to 15 feet wide, with an upright to rounded shape. Older trees with more water can grow taller, so leave room overhead for at least 20 feet.
How fast does Mulga grow?
Mulga grows slowly, and more water speeds it up. Too much water gives it an open, rangy canopy, so once it is rooted stick to a deep soak every 2 to 3 weeks in summer.
How far apart should I plant Mulga Acacia?
Plant about 12 to 15 feet apart, center to center, for a screen, or 15 to 20 feet apart for a looser group. The Spacing tab lays out both.
Is Mulga good for a privacy screen or windbreak?
Yes. It keeps its dense, silvery leaves all year and is often planted in small groups as a screen or windbreak. Space the trees about 12 to 15 feet apart for the fullest screen.
Can I plant Mulga near my pool?
Yes, it is a common poolside choice. It has no thorns and drops little litter, so cleanup stays light. Keep it out of spots where the soil stays wet, since soggy soil can rot the roots.
Does Mulga Acacia have thorns?
No. Mulga is thornless, so you can plant it right beside patios, walks and pools.
How much water does Mulga need?
For the first two weeks, water a new tree every 1 to 2 days in summer, then ease to about weekly by the second month. Once rooted, soak it 2 to 3 feet deep at the canopy edge about every 2 to 3 weeks in summer and monthly in winter.
Can I plant it in my lawn?
It is better not to. Lawn watering keeps the ground too wet for Mulga, and soggy soil can rot the roots. Plant it in a desert bed with other low-water plants instead.
How cold hardy is Mulga Acacia?
It is hardy to about 15°F and keeps its silvery leaves through a Valley winter. Cover young trees with frost cloth on the coldest nights until they are established.
When does Mulga bloom?
Mostly in spring, with small, rod-shaped yellow flowers. It can bloom several times a year.
How should I prune Mulga?
It needs very little pruning. Shape it and raise the canopy slowly as it grows, and never take more than a quarter of the leaves in a year. Finish before monsoon season starts in mid-June.
Does Mulga need to be staked?
Only if it cannot stand on its own or sits in a windy spot. Take off the nursery stake, use two stakes outside the root ball with soft, wide ties, and remove them after about a year.
Should I get Mulga or shoestring acacia?
Shoestring acacia grows taller, often 20 to 40 feet, with a slender, upright shape and weeping leaves. Mulga stays smaller, slower and denser, so pick it for a screen or a small yard.
Mulga Acacia for sale in Arizona, delivered to you
Mulga Acacia is a thornless Australian evergreen with silvery gray-green leaves and a dense, upright shape. It is a slow, tidy grower used as a screen, a patio tree or a poolside tree on low water. Below is what to expect in a Valley yard, from size and spacing to water, cold and bloom.
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Mulga Acacia in Arizona
Mulga is an evergreen tree from the dry outback of Australia, where it is the main tree across large areas. In the Valley it is planted for its silvery gray-green leaves, upright shape and low water use.
How big does Mulga Acacia get?
Plan for about 15 to 20 feet tall and 10 to 15 feet wide. It grows slowly and keeps a dense, upright to rounded shape. Older trees with more water can grow taller.
How far apart do you plant Mulga Acacia?
For a screen, plant Mulga about 12 to 15 feet apart, center to center. For a looser group, space the trees 15 to 20 feet apart. The Spacing tab on this page lays out both.
Is Mulga Acacia a good privacy screen?
Yes. It holds dense, silvery leaves all year and has no thorns. It is often planted in small groups as a screen or windbreak.
How often do you water Mulga Acacia?
Once it is rooted in, soak it 2 to 3 feet deep at the edge of the canopy. Do that about every 2 to 3 weeks in summer and about once a month in winter. Soggy soil and poor drainage are what it handles worst, so keep it out of lawn areas.
Mulga Acacia near pools and patios
It has no thorns and drops little litter, so it is a common choice near pools and patios. Its size fits smaller yards and tight spaces.
Mulga Acacia vs shoestring acacia
Both are thornless, evergreen acacias. Shoestring grows taller, often 20 to 40 feet, with a slender, upright shape and weeping leaves. Mulga stays smaller and denser, which suits a screen or small yard.
When does Mulga Acacia bloom?
Small, rod-shaped yellow flowers show up mostly in spring. It can bloom several times through the year.
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