Importance of Pruning an Acacia
Growing naturally with no pruning, the acacia tree tends to sprout multiple trunks and wispy branches that droop. If you don’t cut back an acacia and shape it for a single trunk, it will stay fairly small and look more like a large shrub than a tree. With pruning, however, you get a shapelier, single-trunk tree that grows to about 15 to 20 feet (4.5 to 6 m.) tall. It’s up to every gardener to decide if they want an acacia that looks more like a tree or a shrub, but even if you want a multi-trunk, shrubby plant, occasional pruning is important to maintain a pleasing shape. The most important time for pruning is when the tree is still young. As it matures, you won’t have to trim it as often.
How to Prune Acacias
Trimming an acacia is much like trimming any tree, except you have big, scary thorns. Always wear long gloves when working on your acacia. To prune your acacia into a single-trunk tree, begin in the first year, trimming in early spring. In the first year, find the central leader, which will be your trunk. Prune off the side branches from the bottom third and shorten the branches in the middle third. In the second and third year of your young acacia’s life, again remove the shoots from the central leader’s bottom third. Shorten the branches in the middle third, and trim out crossing branches in the upper third. In the next couple of years you can trim off side branches to whatever height you want the main trunk to be, and from here on out, you only need to trim crossing, diseased, or dead branches to maintain health and shape. To trim a young acacia to be shrubby, you want to cut back the central leader early. Next year you should see additional branches coming from the central leader. Choose the best ones and cut back the rest all the way to the trunk. In the following years, trim side branches to shape the shrub around the handful of trunks you chose.
