Acacia Tree Care Tips: How to Grow Acacia Trees

A great number of shrubs and trees comprise the genus Acacia, which is part of the pea family Fabaceae and the subfamily Mimosoideae. They grow natively in Africa and Australia, Mediterranean climates, and the grasslands of North America, South America, Europe, and Asia. In the United States, different species of Acacia can be found in California, Texas, Arizona, and Hawaii. Acacia trees and shrubs are technically legumes, meaning they reproduce using seed pods, which are transported by birds, insects, and small mammals. They cannot self-fertilize.

Acacia trees and shrubs stand out for several key characteristics.

1. 1. Pinnate leaves: Acacia leaves are compound and bipinnate. They grow in rows that surround a central stem. This gives some species of acacia a feathery, fern-like quality.
2. 2. Phyllodes and cladodes that look like leaves and stems: Not all acacia "leaves" are actually leaves. Some are phyllodes, a type of modified leaf petiole that connects to branches in place of leaf stalks. Some ostensible stems are actually cladodes—essentially photosynthetic stems. Meanwhile, other acacia leaves and stems truly are what they appear to be.
3. 3. Small but vibrant flowers: Acacias are flowering plants. Most produce either yellow flowers or white flowers. These flowers have minimal petals and vibrant, showy stamens. They can be found clustered together in either spherical heads or in elongated spikes.
4. 4. High tannin content: Acacia wood has a high tannin content. For this reason, acacia trees are sometimes used in the making of leather.

Hundreds of acacia species exist in the African and Australian savanna, with others found scattered throughout the earth's warm, arid regions. Consider a few notable species.

1. 1. Black acacia (Acacia melanoxylon): Black acacia is an evergreen acacia known for its dark brown bark, purple fruit, bluish-green leaves, and spiky, creamy white flowers. Some gardeners call it a blackwood acacia.
2. 2. Golden wattle (Acacia pycnantha): The golden wattle is the national flower of Australia. It is prized for its fragrant yellow blooms and its tannin-rich bark. It grows throughout the southeastern part of the Australian continent.
3. 3. Silver wattle (Acacia dealbata): Although often grown as a small tree, this plant species can sometimes grow over thirty feet tall while remaining dense like a shrub. It grows natively in eastern Australia.
4. 4. Creeping wattle (Acacia saligna): Also called the blue leaf wattle, this species is native to western Australia. The wattle tree grows in full sun and produces massive blooms of yellow flowers.
5. 5. Late flowering black wattle (Acacia concurrens): This species, which grows in eastern Australia, has spikey, ball-shaped flowers that bloom in late winter or early spring.
6. 6. Sweet wattle (Acacia suaveolens): This large shrub grows in coastal Australia. Its creamy white flowers are extremely fragrant and attract many types of pollinators.
7. 7. Sweet acacia (Acacia farnesiana): Not to be confused with sweet wattle, this is a massive tree that can grow up to fifty feet tall. It grows natively in all of the world's inhabited continents. Its stems contain sharp thorns, which has earned it the nicknames thorn tree, needle bush, and huisache (which means "many thorns" in Mexico's Nahuatl language). Its leaves mimic that of the mimosa tree.
8. 8. Acacia koa (Acacia koa): Acacia koa is an iconic wide-spreading shade tree that is native to the Hawaiian islands. Its beautifully figured wood makes it a valuable species for building everything from guitars to surfboards.
9. 9. Kangaroo thorn (Acacia paradoxa): The kangaroo thorn is an acacia shrub that can be used as a hedge. It spreads rapidly and is considered invasive in parts of Australia, South Africa, and California.
10. 10. Sudan gum arabic (Senegalia senegal or Acacia senegal): This plant goes by many common names including Sudan gum arabic tree, gum acacia, Kher, and Khor. It grows in Sub-Saharan Africa, India, and parts of the Middle East.
11. 11. Camel thorn (Vachellia erioloba): Camel thorn is a famous African acacia that is also known as a giraffe thorn due to its appeal to the long-necked herbivores. It produces light gray thorns and bright yellow blooms. Its seed pods attract a wide variety of animals including wild cows.

Acacia trees and shrubs are prized for their beauty, but they also play an important role in various industries.

1. 1. Tanning: Thanks to the intense tannins in acacia wood, the species is used in tanning and various forms of leather work.
2. 2. Woodworking: Some luthiers seek out koa wood for constructing guitars. The wood can also be found in surfboards and canoes.
3. 3. Dyes: The seeds of coastal acacia can be used to make green dye while its flowers can be used for yellow dye.
4. 4. Gums: Acacia gum arabic is used as a food additive, as an adhesive, and as a cosmetic.
5. 5. Perfume: As flowering plants, acacias have been used in perfume manufacture. This is particularly true of the fragrant golden wattle species.

Some species of acacia trees can fit a large lawn, while many acacia shrubs can add color and fragrance to your garden. Consider some tips for growing and caring for acacia trees.

1. 1. Hardiness: Acacia trees and shrubs do best in Mediterranean climates and can also survive in the hot savanna. In North America, they do best in USDA hardiness zones nine through eleven.
2. 2. Soil: Acacias need well-draining soil. Sandy soil is ideal, but loam also works. Heavy clay may retain too much water.
3. 3. Sunlight: Acacias naturally grow in full sun. Most tree species tower over other plants and function as shade trees. Shrubs and smaller trees can also do well in partial shade.
4. 4. Watering: Acacia trees put down deep roots that help them survive many years of drought. Water young saplings at least once a week. Mature trees need nothing more than the water nature provides.
5. 5. Pruning: Prune your acacia during the dry season to encourage new growth and thicker foliage.

Many species of acacia are used in food additives and are generally safe. However, certain species—including Acacia adunca, Acacia acinacea, Acacia acuminata ssp. acuminata, and Acacia burkittii—produce a psychoactive alkaloid called dimethyltryptamine (DMT).

In everyday encounters, you must be mindful of acacia thorns, which grow in many species of trees and bushes. Plant thorny acacias in a remote part of your garden to avoid accidental injuries.

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