Acacias are members of a large family of trees and shrubs that are found in tropical areas and evoke African savannahs or the Australian outback. With their fern-like leaves and yellow (or sometimes white or pink) clusters of gorgeous flowers, these trees are widely grown for their beauty.
You may have acquired a strong liking for acacias if you have been lucky enough to take an African safari or a trip to Australia. Or perhaps you have admired them from evocative photographs.
If you live in a cooler climate or do not have the room for such aggressively growing plants, do not despair! Many species of acacias are excellent subjects to train as bonsai trees as long as you provide the conditions they like! Lots of light is paramount!
Be prepared to aggressively prune their branches and roots, since these plants grow vigorously. Some species have thorns, so keep that in mind if you have curious children or pets that like to graze on your plants.
One desirable feature of Acacia trees and shrubs is that they have bacteria on their roots that help them add nitrogen to the soil. Don’t worry if you see weird round structures on the roots. These are the “nodules” of bacteria where they do the heavy lifting to transform nitrogen in the air into forms that the plants can use as a natural fertilizer.
Scientists even recommend planting Acacia on poor quality soils to provide nitrogen fertilizer for crops.
Care Guidelines For Acacia Bonsai
Read on to learn how to grow your very own acacia bonsai tree.
Unless you live in a hot and dry climate, acacias need warm, sunny, and airy sites. If you do live in a hot, dry area, keep the plants out of the hot afternoon sun during the summer.
If your area has cold winters, you will need to keep your acacia bonsai either indoors or in a heated greenhouse. Acacias grow best at temperatures between 12 and 20ªC (53 and 68ºF).
However, if you can provide a lot of sun and humidity, warmer temperatures are fine.
These bonsai trees are not fussy about water. Don’t let the roots dry out completely, but don’t overwater them either. Your best bet is to check the top inch of soil, and water when it dries out. Try not to use hard water, which has a lot of calcium in it.
Soil And Fertilizing
Since most Acacias can obtain nitrogen from the air, they do not need as much fertilizer as other types of trees. Therefore, choose a fertilizer that is low in nitrogen.
Also, they only need to be fertilized during the growing season. You can use a liquid fertilizer every other week or solid organic fertilizer once a month.
If your tree is kept in a cool place during the winter and not growing much, you only need to fertilize once a month with liquid fertilizer.
Since Acacia bonsai trees grow quickly, you will need to trim them regularly. Shorten the new shoots in the spring and summer. Remove all but one or two leaves in early spring. This is known as nipping. Reserve your heavy pruning for the winter, and be sure to leave stubs, or the plant may contract a disease. Remove these stubs after they have dried.
Young Acacia bonsai trees should be repotted every 2-3 years, while older ones can be repotted every 3-4 years. Do this in the early spring. Be judicious when you prune the roots, and be careful not to disturb the root nodules since they absorb nitrogen for the trees. Make sure that the soil mix you use drains well and has an adequate amount of humus in it.
You can grow new plants from cuttings or seeds. It is easier to grow new plants from seeds.
Potential Pests And Diseases
Fortunately, acacia trees are vigorous and usually resist attack by diseases and pests. However, if your tree is stressed, it can attract aphids or scale insects. Neem oil should be effective against these pests. Plants can also succumb to root rot if they are overwatered. That kind of fungal disease is typically fatal.
Wiring Your Bonsai
Wiring with aluminium is important to make sure that your acacia has a nice shape. The best time to do this is when the tree has no leaves, like in the late spring. You can easily shape the young twigs, since they are flexible. However, the older branches tend to be brittle. Be careful that you do not damage the bark as you shape your tree.
Q. How Long Does Acacia Bonsai Take To Grow?
A. Eight To 10 Years.
If your acacia bonsai tree starts at 15 centimeters, it should reach approximately 45 cm in eight to 10 years. One important step to take is pinch back the leaves in the early spring. This is known as leaf nipping and will make it easier to train your tree to a delightful shape.
Q. How Do You Grow Acacia Bonsai From Seed?
A. Make sure that you purchase a seed mix that drains freely. The seeds must be pre-treated before you can plant them. If you don’t do this, water will not be able to penetrate the hard seed coat. One option is to put the seeds in a container and cover them with water that is almost boiling. Let the seeds sit overnight, and then choose the ones that have swollen. Another option is to rub the seeds between two pieces of sandpaper. This should allow water to penetrate the seed coat. Use a covering to keep the growing environment humid. This could range from plastic cling wrap to a growing dome that you can purchase.
Q. How Often Should I Water My Acacia Bonsai?
A. There is no hard and fast rule on how frequently you should water your tree, since it can dry out at different times depending on its growing conditions. Check the top inch of soil every other day, and water thoroughly when it is dry. It is highly important the roots stay moist. However, if they are kept too wet, they may rot.