This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Of this extensive genus only a very few are available for market culture, as the majority of them must attain tree-like dimensions before they flower well. A case in point is furnished by A. dealbata, the "Mimosa" of florists' shops. If this could be flowered in a small state there would be a great demand. The best of the Acacias for this purpose are armata, cordata, Drummondii, grandis, ovata (or obliqua), and verticillata.
Acacias need more care in their propagation than the bulk of plants commonly grown for market. They are increased by cuttings of the half-ripened shoots, taken during the spring or early summer, and inserted into well-drained pots of sandy soil. They must be kept close and shaded either under a bell glass or in a close propagating case. During the earlier stages they make more headway in a structure warmer than an ordinary greenhouse. When rooted and hardened off these Acacias should be potted singly into small pots, using a mixture of loam, peat, and sand. For cordata and Drummondii an additional allowance of peat is beneficial. Directly the roots take hold of the new soil the tops of the plants should be pinched out in order to encourage a bushy habit. These Acacias flower during the spring months, and as those which are struck one spring are too small for sale the next, they are as a rule kept for two years. The more vigorous examples are then established specimens in 5-in. or 6-in, pots.
From the length of time necessary to get well-furnished plants, Acacias of course realize higher prices than quicker-growing subjects. As they flower naturally in a greenhouse temperature they may be used for decorative purposes in places where other plants grown in greater heat would quickly suffer. Seeds of some kinds can be occasionally obtained, but plants raised in this way do not flower so freely in a young state as those propagated from cuttings. One species, lophantha, is grown for its pretty Fern-like leaves. This may be increased from seeds sown in heat in early spring, and the young plants so obtained make rapid progress afterwards. It is much used as a "dot" plant in summer bedding, [w. T].