Actual size and flowering may vary slightly based on season.
White Thorn Acacia
White Thorn Acacia is a small Sonoran Desert tree known for its sweet-smelling yellow puffball flowers in spring and again after the summer rains. It grows about 10 to 15 feet tall and wide, usually with several trunks and fine, fern-like leaves. Once rooted it lives on very little water, and bees and birds visit it. It fits patios, narrow side yards and natural desert landscapes.
Best for: a small tree for patios and narrow yards, fragrant spring and late summer flowers, bees and birds, natural desert landscapes, and a thorny barrier along a property line.
At about 10 to 15 feet tall and wide, it fits patios and narrow spaces where a big shade tree would crowd the house. The fine leaves soften the summer sun without blocking it. Train it to one trunk or keep several for a natural look.
Sweet-smelling yellow puffballs open in spring, and a second round follows the summer rains. Plant it where you walk past or sit outside so you catch the scent.
Bees work the flowers, and quail and other birds eat the seeds and use the branches for cover. Its fine leaves cast light, filtered shade. Once rooted it gets by on very little water.
Young stems carry paired white thorns up to about an inch long, so keep it back from walkways and play areas. Thin reddish brown pods drop in late summer and fall, and it drops its leaves in cold or very dry spells.
- Barrier or informal hedge10 ft apart
- Trees with room to spread12-20 ft apart
A new tree needs water every 1 to 2 days in summer for its first two weeks, or every 3 to 4 days when it is cool. Stretch that to about weekly by the second month, and keep watering deeply for about 3 years. After that, a deep soak at the canopy edge about every 2 to 3 weeks in summer and about monthly in winter is plenty.
Remove the nursery stake when you plant. If the tree leans or the spot is windy, set two stakes outside the root ball with soft, wide ties that let it sway a little. Take the stakes out after about a year.
Shape it while it is young into one trunk or a few strong ones. Remove no more than a quarter of the canopy in a year, and never strip the inside so only branch tips are left. Finish any thinning before monsoon season starts in mid-June.
Frequent watering or soggy ground can lead to root rot and yellow leaves. Deep soaks with dry spells in between suit it best.
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 White Thorn Acacia get?
It usually grows about 10 to 15 feet tall and about as wide. With extra water it can reach close to 20 feet, so give it room to spread.
How fast does it grow?
It grows slowly on rainfall alone and at a moderate pace with extra summer water. More water gives faster growth and a bigger tree.
Does White Thorn Acacia have thorns?
Yes. Young stems carry paired straight white thorns, from about a quarter inch to an inch long. Older branches often have few thorns, but wear gloves when pruning and keep it off walkways.
When does it bloom, and are the flowers fragrant?
It blooms in spring, then again in late summer after the monsoon rains. The small yellow puffballs are sweetly fragrant, so plant it near a patio or path to enjoy them.
How much water does it need?
Very little once it is rooted. Give it a deep soak at the edge of the canopy every 2 to 3 weeks in summer and about monthly in winter, not at the trunk.
Why did my White Thorn Acacia lose its leaves?
It drops its leaves in cold winters and in long dry spells, then leafs out again with warmth and water. Bare branches in winter are normal and the tree is not dead.
How cold hardy is it?
It is hardy to about 0 to 5°F, well below a normal Valley winter. Cold makes it drop its leaves, but it needs no frost cover.
Is it messy?
It drops a moderate amount of litter. Thin reddish brown pods, 2 to 5 inches long, follow the flowers and drop, so keep it away from pools you want clean.
Does it attract bees and birds?
Yes. Native bees and honey bees visit the flowers, and quail and other birds eat the seeds and use the tree for cover.
Is White Thorn Acacia native to Arizona?
Yes. It grows wild in washes, rocky slopes and desert flats across southern Arizona, and into New Mexico, Texas and Mexico.
How do I prune it into a tree?
Shape it while it is young, choosing one trunk or a few strong ones and removing low or crossing branches. After that, prune only as needed to shape it and keep it clear of walkways.
How is it different from Sweet Acacia?
White Thorn Acacia blooms in spring and again after the summer rains, and drops its leaves in winter. Sweet Acacia blooms in late winter, keeps most of its leaves and grows larger.
White Thorn Acacia for sale in Arizona, delivered to you
White Thorn Acacia is a small, tough desert tree that grows wild across southern Arizona. It blooms with fragrant yellow puffballs in spring and again after the monsoon, and lives on very little water. Below: size, growth, thorns, bloom, water, winter leaf drop, pods and how it compares with other acacias.
Sourced from trusted Arizona growers and delivered directly to your door, job site, or property. We deliver across the Valley and to nearby towns, and quote delivery anywhere else in Arizona.
How big does a white thorn acacia get?
It grows about 10 to 15 feet tall and wide, often with several trunks. With extra water it can reach close to 20 feet. That size suits patios and narrow side yards.
When does white thorn acacia bloom in Arizona?
It blooms in spring and again in late summer after the monsoon rains. The yellow puffball flowers are sweetly fragrant and busy with bees.
White thorn acacia thorns
Young stems carry paired white thorns up to about an inch long, which give the tree its name. Older branches often have few thorns. It can be trained into a thorny barrier along a property line.
How often to water white thorn acacia
Once rooted it needs very little water. A deep soak at the edge of the canopy every 2 to 3 weeks in summer and monthly in winter is plenty.
Does white thorn acacia lose its leaves?
Yes, it drops its leaves in cold winters and long dry spells. It leafs out again with warmth and water, and it is hardy to about 0 to 5°F.
How far apart to plant white thorn acacia
Plant them about 10 feet apart for a barrier or informal hedge. Give trees that should spread on their own 12 to 20 feet.
White thorn acacia vs sweet acacia
White thorn acacia blooms in spring and after the summer rains and drops its leaves in winter. Sweet acacia blooms in late winter, keeps most of its leaves and grows larger.
We deliver across the Valley, from Phoenix, Scottsdale and Mesa out to San Tan Valley, Maricopa and Casa Grande, and up to Prescott, Sedona, Payson and Globe. See delivery areas and rates.