When the Hebrew people left Egypt on their way to the promised land, they took acacia wood with them. Eventually, tablets inscribed with the Ten Commandments would be placed in an ark fashioned from this wood.
It is only proper that the acacia, with its holy heritage, should grow well in Los Angeles, the City of Angels. Phil Chandler, in his book on ornamental plants for Southern California, lists 26 acacia species for various garden situations.
Acacias accept hard soil and smog. They demand little water. They bloom in gold magnificently this time of year. Acacias are among the saints of the plant kingdom; they give constantly and ask for nothing in return.
The ultimate testimony to the durability of a plant is its selection by the state Department of Transportation for freeway landscaping. This month, stuck in some unholy traffic jam, you may have noticed acacias blooming along the highway. If you saw an upright growing plant with pale green leaves and long golden flower spikes, you were looking at Acacia longifolia, the Sydney golden wattle. If you saw a trailing plant, with sulphur yellow, half-inch spherical blooms and blue-gray foliage, you were gazing upon Acacia redolens.
Acacias answer the prayers of homeowners who want trees that grow quickly but, at maturity, are no taller than 20 or 30 feet. The most popular species in this respect is the golden mimosa, Acacia Baileyana. One of the earliest blooming trees, it has all but finished flowering this year, a consequence of the record heat spells we experienced in January and February. Acacia Baileyana “Purpurea,” a variety with violet-colored leaves, provides an added measure of ornamentation, and may be grown as either a large shrub or tree.
The leaves of Acacia Baileyana, like those of several other acacias, are finely cut and doubly pinnate, giving the canopy a soft, feathery look. The jacaranda, an unrelated tree, has similar leaves and is associated mistakenly with acacias for this reason.
The name mimosa, by which fine-leaved acacias are known in Europe and America, can be traced to Mimosa pudica, the “sensitive” plant or touch-me- not whose leaves collapse upon being touched.
In East Africa, acacias are known simply as “thorns,” since the species native to that part of the world are distinguished by – that’s right – long, piercing thorns. Thorniness is often explained as a defense against predators; however, anyone who has seen a giraffe devouring an acacia tree, thorns and all, will acknowledge the folly of this thinking. Additional proof comes from roses, the impressive thorns of which have never prevented deer from consuming whole floribundas, grandifloras and hybrid teas.
Thorns appear to be a sign of drought tolerance. It is thought that thorns are modified leaves, without the surface area for water loss. Thorns and spines – such as those on cactus – may by efficient at collecting dew and channeling it to stems, from where it drips onto the soil and is finally taken up by roots, providing a measure of moisture to certain dry-climate plants.
Acacia Farnesiana, named sweet acacia for the fragrance of its flowers, is a thorny, deciduous plant which grows to 10 feet and is native to Central America and Mexico. Easily raised from seed, sweet acacia has wicked thorns which make it the ideal living fence, a barbed wire species that forms a hedge no outlaw would dare to cross. Acacia subporosa, on the other hand, is a highly prized, gently pendulous tree with a contrastingly calm and composed demeanor.
Plants such as acacias that grow quickly to their mature height have one drawback: They are short-lived. Remove dead growth immediately. To enhance the longevity of acacias, treat them as if they were California natives – that is, keep watering to a minimum.