Mimosas are coveted for their graceful limbs and trailing, fernlike flowers, making it a lovely feature in the home landscape. Mimosa trees are best grown in warm climates, so it's difficult to grow them in the UK outside of a greenhouse. For the intrepid gardener, however, it can be done with careful nurturing. Like most trees, pruning a mimosa is best done in the fall, when the tree is dormant.
Approach pruning with caution, because once you cut a branch away, you cannot put it back. Study your mimosa before you prune, and decide what shape you would like to end up with.
Decide whether you want a tree with multiple trunks, or just one. Prune trunks away at the base of the tree with a pruning saw if the latter is the case, leaving the strongest one.
Move higher on the trunk, clipping away low-growing branches with pruning shears to help the tree gain more height. Mimosas grow fast, but doing this will further accelerate vertical growth. Cut branches so that you're left with a half-inch stub, because the bark of the trunk can be easily damaged by shearing at its surface.
Work your way into the canopy, keeping in mind that mimosas naturally have a delicate, lacy spread at the crown. Less pruning is needed to gain adequate light penetration at the centre of the tree canopy.
Prune away any dead or diseased wood as you find it. Mimosas in the UK are increasingly vulnerable to verticulum wilt and other diseases.
Repeat pruning annually, clipping away new shoots that appear at the base of the tree.
- Mimosas in the UK are best grown in greenhouses, or outdoors in large containers that can be wheeled inside during the worst of the winter months.
- Don't get too attached to your mimosas. They will only live for about 20 years, and do not transplant well.