Acacia belongs to the Leguminosae family which also includes the Powder Puff, Brazilian Rain Tree and Tamarind among others. There are over 1000 species of Acacia trees and shrubs found mostly in sub-tropical and tropical regions, most commonly Australia and Africa. About 75% are Australian species, but those considered the most beautiful are from Africa. The Australian species do not do as well in high humidity climates. When seen in nature at maturity, the Acacia has few if any lower branches and a spreading crown.
Here are a few varieties suitable for bonsai:
Acacia farnesiana Sweet Acacia. A thorny plant with delicate, bipinnate compound leaves, colorful yellow flowers and brown seed pods.
Acacia choriophylla Thornless Acacia. This tree has long, thick, pinnate, dark green leaflets. Native to the Florida Keys, Bahamas and Cuba. Resembles the tamarind.
Acacia pennatula Feather Acacia. Tree has bipinnate leaves with beautiful red new growth. Leaves reduce very easily.
Acacia cornigera Bullhorn Acacia. This tree is distinctive because of the large, impressive thorns. The tree has a symbiotic relationship with ants. The trees provide nectar to the ants, and the ants protect the tree from invasive plants and pest. The ants reside in the thorns which become hallow with age. Native to South Africa, so are the ants.
PRUNING... Prune back rather hard after blooming, blooms in spring. The leaves are compound, so only cut at a joint, not leaflet. Both the roots and top can be heavily pruned.
TRAINING... Bark is thin and delicate, can scar very easily. Heavier branches you might want to wrap with raffia or florist tape to minimize scarring. Generally trained with an open crown, somewhat flat topped. Think Africa.
WATERING... Fairly drought tolerant, careful not to over water. Allow to dry down between waterings.
LIGHT... Prefers full sun but can tolerate lower light conditions.
INSECT/DISEASE... Havenít really had a problem with any insects or disease.
REPOT... Summer, minimum night temperature-lower to mid 60s. Rather quick growers, but donít mind being a little root bound. Young trees every 1-2 years. Older 2-3 or more years.
FERTILIZE... Low nitrogen fertilizer through blooming season. Then a balanced fertilizer through growing season.
SEASONAL... Protect below 40 degrees.