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Acacias are rugged individualists. They will often sicken and die under abundant watering and feeding in a garden, but will thrive upon neglect. They are drought resistant and many stand cold well. After the freezing weather in Southern California, the acacias were generally unharmed and continued an uninterrupted display of golden color. Many species will endure temperatures as low as 15 degrees.

The use of acacias in the landscape has apparently diminished in recent years due to the injudicious use of certain types as street trees and to lack of consideration of their cultural requirements and best uses.

The vigorous timber tree types including the silver wattle, Acacia decurrens dealbata; the black wattle, Acacia decurrens mollis; and the blackwood acacia, Acacia melanoxylon, are longer-lived than the lower-growing sorts. However, these species have often broken and lifted sidewalks when planted as street trees and have acquired a bad reputation. This objection can be overcome in a large measure by deep root pruning near the trunks of the trees when they are young. Nevertheless, the acacias all have some characteristics which makes their use as street trees questionable, except possibly on exceptionally dry sites where presentable specimens can sometimes be seen growing on as little as 10 inches of rainfall annually.

The small tree and shrub forms are often somewhat short-lived under favorable conditions. However, the beauty of many of these amply justifies the planting of occasional replacements. The knife acacia, Acacia cultriformis; the pearl acacia, Acacia podalyriaefolia; and the blue-leaf wattle, Acacia cyanophylla, have silvery or bluish colored foliage. Acacia baileyana is one of the most common and has a very fine-textured foliage. This species has a purple-leaved variety. Acacia retinodes, commonly sold under the name of Acacia floribunda, would truly deserve the latter name, since it is rarely without flowers. Acacia pendula, the weeping myall, which is common in the interior of Australia, is rarely seen in California, but is a small tree of remarkable beauty of form and foliage. The width of the phyllodes varies considerably in different specimens of this species. Many of these smaller acacias are quite useful in informal border plantings because of their attractive habit and foliage as well as the striking seasonal floral display which they provide.

Many of the acacias bloom in midwinter when flowers are scarce. Acacia podalyriaefolia, Acacia cultriformis, and many others have much value as cut flowers. The attraction of fragrance is also available in acacias. The huisache or popinac, Acacia farnesiana, which is a native of the southwestern states, is not particularly showy, but has a delightful fragrance which makes it worthy of cultivation. This species is native in widely scattered portions of the globe, a botanical mystery difficult to explain.

The Spring garden shows of the eastern cities have been greatly enriched by lavish displays of acacias in pots and tubs from the conservatories of the great estates. These plants require little heat and are easy to grow. Any house suitable for camellias will be satisfactory. Although there are occasional statements to the contrary, the plants may be pruned back severely after flowering to keep them shapely. Practically all types, including the large timber species, are successful in pots or tubs, but naturally those with striking foliage and flowers will give the greatest satisfaction. Acacia armata, Acacia baileyana, Acacia pubescens, Acacia alata, and Acacia longifolia, are a few of the species which will form good specimens.

Some of the acacias are excellent for shearing, both in tubs and when planted in the garden. Sheared hedges and allees of Acacia melanoxylon are a striking feature of some of the estates in the vicinity of Montecito and Santa Barbara, California. Massive effects in formal gardening can be provided in this manner at a moderate cost, thanks to the development of electric and gas-powered hedge trimmers. Acacia verticillata, the whorl-leaved acacia, and the Sydney golden wattle, Acacia longifolia, are excellent for smaller hedges and can also be used for sheared formal specimens in tubs. The latter species combines drought resistance with more tolerance to overwatering than is usual in acacias. There are doubtless many unexplored possibilities among acacias for the patio garden.

Cuttings from greenhouse grown specimens of acacias often root well; but, when available, seeding is the simplest method of propagation. When old, the seed coat of acacia seeds if often hard and impervious and requires special treatments for germination. The seeds may be notched with a file or dropped in boiling water which is immediately allowed to cool. These seeds will also respond to treatments with concentrated sulfuric acid for a half hour or longer. The juvenile forms of seedling acacias often differ considerably from the mature character. Some retain the feathery fern-like, pinnate foliage throughout life, but others, including Acacia melanoxylon and Acacia longifolia, lose all true leaves and develop a thickened structure from the petioles which perform the functions;of leaves and are called phyllodes.

by T Stottlemeyer