Acacias are very easy-to-grow and undemanding trees. These are plants that appreciate a lot of heat, and are relatively tolerant to cold air currents. They do not require enriched soil, but a small supply of potting soil or manure is always welcome to help them grow better. They are often grown for adorning and airing out a sunroom, terrace or balcony. 

Acacias are plants of the Legume family native to subtropical regions like Australia. These are often called thorn trees, whistling thorns or wattles and when grown indoors, they are often named mimosas. There are over 1500 species of acacia worldwide, including more than 1000 in Australia alone, where they are the national flower. They are easy-to-grow plants that adapt well to various climatic conditions, such as those found on coastal areas, in sub-mountainous or arid regions. When grown in the ground or in its natural habitat, an acacia tree can easily reach 10 feet. An acacia tree grown in a container may reach up to 5 feet and its growth is relatively slow. Acacias normally bloom throughout the year, but have a major outbreak between March and April. Their flowers are yellow but some species also bear pink flowers.

Planting and propagating acacias 

The planting period of acacias varies according to species. For bare root plants, it is best to plant them between late October and late March. For species in containers, you can basically plant them the whole year round, but it is better to put them in the ground between September and May. For acacias sold in clumps, the planting period is between October and April. If you have relatively impermeable soil, you can drain it and add a bit of gravel and sand. When planting, add a little fertilizer, potting soil or manure to fertilize the earth. It is advisable to mix the lower half of the hole well and to avoid contact between the roots and the fertilizers to prevent any risk of burns. For whatever type of acacia you wish to plant, it is important to make a hole at least 2 or 3 times the size of the roots, container or rootball. This will allow the roots to be thoroughly aired out and grow faster.

Propagation of acacias is normally done by cuttings. This procedure, carried out during the summer, requires the use of semi-hardwood cuttings taken from lateral branches. It is important to use a clean and sharp knife for the cuttings to grow better. Then dip the bases of the removed cuttings in rooting hormone and plant them in moist sand. It is advisable to place your cutting in a semi-shaded area and cover it with a plastic bag to maintain a temperature of about 70 ? F. When new shoots start to appear, you can repot them and it is recommended to initially place them in a shaded area. If the plant grows relatively well, you can move it in the sunlight.

Maintaining acacias 

Acacias are trees that do not require special maintenance, however they must be provided with the best possible growing conditions in order to thrive. It is important to make a first watering just after planting to fully establish contact between the plant’s roots and the soil. The first watering is essential and should be done even if it is raining. During their first year, it is advisable to regularly water your acacias. However, avoid overly frequent waterings in winter. You can water the seedlings sparingly at first. During the summer, it is important for the root ball not to be too dry. In spring until early September, you can add a bit of liquid fertilizer to your plants at least once a month. An annual pruning is required after the flowering period, as it will allow the plant to maintain its bushy bearing. It is also advisable to trim at least a third of bulky vegetation. Normally, you will not have to worry about anything during strong summer heat; however, attention must be paid in the winter. It is important to maintain a temperature of at least 50 to 59 ? F during the day and at least 45 ? F overnight.

Acacias are often prone to errors of cultivation or victims of disease, but there are solutions adapted to all situations. If you find that the phyllodes are beginning to turn brown or sag in winter, it is probably due to excess water. It is advisable to repot the plant as soon as possible and add dry and well-drained compost. You can also treat it with fungicide. If your acacias are invaded by red spiders, you can treat them with appropriate insecticide or acaricide. Acacias are also victims of obscure mealy bugs that embed themselves under the phyllodes. You can remove them with a pad soaked in rubbing alcohol or you can also treat acacias with a suitable insecticide.

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Published in Trees and shrubs by Alexander on 06 Jul 2011