We have 4 mulberry trees we planted several years ago. Each fall, after the trees go dormant, we trim the trees as per the recommendations. Each spring the trees literally grow 3-4 limbs in each place where we trimmed the previous fall. The end result over several years is that the trees have a sizable trunk but look very much like a wild bush with limbs growing everywhere in all directions but up. We just can’t get upward growth; it’s always outward. I’m sure we’re doing something wrong but am out of ideas. Please, do you have any suggestions to help us recover from the revenge of our mad mulberry bushes? Janet S.
Answer: Mulberry trees are loved by birds for their juicy fruits but these trees are such rapid growers and self-sowers that many consider them to be weeds. Any time you have trees or shrubs that are such aggressive growers, you usually have to implement some equally aggressive pruning to keep them looking good. When training a tree you want to ensure that you have a central leader or main trunk. Sometimes these get damaged when they are seedlings and that limits the plant’s ability to grow in a “normal” tree form and become more bush-like. A new leader can often be trained if this happens, but it takes some work with young branches and is almost impossible with older trees. It’s a lot like training a tree into an espalier (flat, groomed) form.
For mature trees it’s important to know where to cut to limit that over-sprouting of new growth. Here are a few tips. All pruning does not need to be done in the winter. It does help to see branching structure but is not requisite. It is also not necessary to treat wounds with tree paint. If made correctly, the tree will heal these cuts and fend off any parasites. When trimming, it’s better to take branches back to either the main trunk or to a larger adjoining branch. This will help eliminate the dense growth at the ends of pruned branches. This growth is not only weak and subject to damage or disease, but it also gives the trees a leggy or wild appearance.
Do a search online for state extension colleges. Most all consumer horticulture offices have great publications about pruning, including detailed drawings or photos on exactly where to cut. Once you have read through these you will know exactly where to trim all your trees and shrubs.
Just remember, never ever top trees. It only creates weak and dangerous trees.
Good luck, Karen