Sweet Acacia
Sweet acacia is not a particularly common landscape plant, likely because of its sharp spines. But gardeners willing to give this plant a try will be rewarded with fragrant, bright, yellow blooms. Sweet acacia's scent is famous worldwide and even used in perfumery. This native tree is a treat for your senses and very low maintenance.
Characteristics
Sweet acacia (Vachellia farnesiana) features small yellow "puff" flowers. These blooms appear in clusters in late winter or early spring. It continues to bloom after each new flush of growth. In Florida's mild climate this means a long season of bright yellow flowers.
But even when it isn't flowering, sweet acacia makes an attractive landscape plant. Dozens of soft-green leaflets make up its feathery foliage. The zig-zag stems are olive green to gray and covered with sharp, light gray spines. These spines are about 1 inch long and appear at the base of the leaves.
And sweet acacia produces more than fragrance. This tree also serves as a nesting site for birds. The spines deter would-be predators and the birds enjoy its seeds. A Florida-Friendly plant, this multiple branched tree often attracts wildlife. Even white-tailed deer have been known to enjoy the pod-like fruits.
This image provides a look into the irregular crown of this artistic tree. Photo: Dr. Sandra Wilson
As a small tree, sweet acacia reaches a maximum height and spread of 15-25 feet. It can also be maintained as a large shrub or even in a planter. Regardless of growth habit, the crown of this plant is rounded, irregular, and spreading.
Landscapers planted sweet acacia extensively throughout southern Europe, wishing to enjoy its scented flowers. It is semi-evergreen, meaning that it keeps some of its leaves during mild winters. In the U.S. it thrives in USDA hardiness zones 9a – 11.
Finally, this plant is an excellent replacement for the invasive mimosa tree, Albizia julibrissin. It provides the same eye-catching landscape presence, delicate foliage, and puff-ball flowers. Better still, it will not displace native vegetation.
Planting and Care
Vachellia farnesiana does not do well in the shade of larger landscape trees. For best results plant your tree in an area where it will receive full sun. Once your tree is established, water only occasionally. Once or twice a month during the growing season is plenty. Sweet acacia is highly drought tolerant. That said, it may defoliate (lose its leaves) if the drought is severe enough.
Sweet acacia will grow well year-round in South and Central Florida. Gardeners in northern parts of the state should protect the tree from frost during the winter. It tolerates some salt and sites that are nutrient poor. It will grow in a variety of soil types if the soil is well drained.
Sweet acacia can be pruned into a small tree. This tree is young, but may someday grow to a height and spread of 25 feet.
Photo: Dr. Sandra Wilson
As a tree, Vachellia farnesiana maintains a shrub-like growth habit. It is multi-stemmed with wispy, drooping branches. There is a lot of natural variability in its branching structure. Gardeners can select for this in younger plants, and properly prune it to maintain a single trunk.
Seed is the preferred method of propagation. Wait until the green pods turn brown to collect fruit. Before planting, the tough seed coats will need to be loosened. This will improve the seeds' chances of germinating. The process of loosening a seed coat is called scarification. To do this, remove the seeds and soak them in hot water overnight, allowing them to slowly cool. If you are in a hurry, rub them lightly with sandpaper instead. New plants will sprout in less than two weeks.
In addition to a low-maintenance watering schedule, this plant boasts almost no pest management concerns. But, while sweet acacia has many desirable qualities, it also has a thorny side. Plant it in an area where children and visitors will not come in contact with its sharp spines. Most gardeners find that this a small trade-off for such a vibrant addition to their landscape. This Florida native brings heavenly scents, brilliant blooms, and thrives in our unique climate.
For more information on sweet acacia, contact your county Extension office.