Question
In live in Northern NJ. Our Crepe Myrtle has been in the ground 2 or 3 years and is about 7 feet high. When is the best time of year (if any) to cut it back and how much should I trim?
Thanks for your time. Jon
Answer
The ideal crepe myrtle pruning time is either in the late winter or early spring when the tree is in its dormancy. In your area I would say early March. This is the best time to prune if you are reshaping the tree, removing deep or weak branches, trying to encourage new growth or size maintenance.
Before going into how to prune crepe myrtle trees, we need to look at if you need to prune you crepe myrtle at all.
While pruning crepe myrtle trees is good for helping to keep the tree shaped like you would like it to be, it is not normally necessary to the health of the tree. Prune crepe myrtle trees when you wish to shape them or if you find the branches are too close together for your taste, but for the most part, you do not need to prune crepe myrtle trees.
There are two schools of thought when it comes to pruning crepe myrtle trees. One is a natural style and the other is a formal style.
Natural style
A natural style of pruning will mostly address the limbs within the tree that may be keeping your crepe myrtle tree from putting on the best show it can. Things like inward growing branches, damaged branches, branches that are too close together or rubbing against each other and other minor issues that could affect the canopy of the tree. Smaller inside branches may also be removed to open up the space inside the tree. With a natural style of pruning crepe myrtle trees, main branches will be left alone to promote thick sturdy trunks.
Formal Style
With a formal style, when you prune crepe myrtle trees, you are pruning for outward shape rather than inner openness. Formal style pruning is also thought to encourage additional blooming since it forces the tree to grow more new wood, which is where blossoms are formed. In a formal style, the decision on how to prune a crepe myrtle tree is based on how high and how wide you would like the tree to be. All branches outside the chosen dimension is cut off, much like you would trim a hedge. This style of pruning can keep crepe myrtle trees in the same landscape setting uniform in size and shape and lends a more formal look to them.
Here is a web link to more information on pruning crept myrtle
http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1009.html
