If tree pruning is part of the care program, almost all maple species show their squeamish side. However, you don't have to accept unbridled growth and wildly gesticulating branches. This guide explains when and how to skillfully prune a maple tree.
When and how should you prune a maple tree?
Maple trees should be pruned in the fall when sap flow is low. Prepare sharp, disinfected tools and cut back long shoots in annual wood. Make the cut at an angle a few millimeters above a leaf node or sleeping eye to allow rainwater and plant sap to drain away.
Best cutting date is in autumn
On most maple species, growth is characterized by a strong flow of sap, which only slows down for a short time in autumn. If you prune the tree in the middle of the growing season, the sap will flow freely. In order to prevent bleeding, the choice of date for tree pruning primarily takes this special property of maple trees into account. These criteria characterize the best time:
- Mild, dry weather in autumn
- No blazing sun, no rain and no frost
To prune a maple tree without heavy sap flow, the measure should be completed by mid/end of January at the latest. On species and varieties that sprout early, the sap pressure increases in late winter.
Two exceptions to the appointment rule
The schedule for tree pruning is of course not firmly cemented for autumn. Robust field maple (Acer campestre) and Asian slotted maple (Acer palmatum) are two exceptions to the rule. To ensure that field maple maintains its well-groomed appearance as a fast-growing hedge, you can cut back shoots that are too long in autumn, early spring and again in June. The picturesque varieties of slot maple are ideally cut in spring, shortly before the leaves emerge.
Preparation work – what you should pay attention to
The sword of Damocles of fungal infections dangles over every tree cut on the maple tree. Please do not trim the tree or shrub until you have cleaned the cutting tool and disinfected it with alcohol. Beforehand, sharpen the blades with a whetstone so that the cuts do not fray and attract pathogens.
Also protect your skin and clothing from the sticky plant sap. Even in the midst of dormancy, the syrupy liquid flows from the bark in small amounts when you prune the branches.
Cutting guide leaves old wood untouched - Here's how it works
The careful choice of dates in autumn and the recommended preparations are the perfect start to professional tree pruning. If you follow these instructions for the cut, you have done everything right:
- Cut back branches that are too long only in the area of annual wood
- Make a cut a few millimeters above a leaf node or sleeping eye
- Cut slightly at an angle so that rainwater and plant sap can run off
A characteristic feature of maple is that the tree or shrub from old wood does not sprout again or grows out hesitantly. Therefore, limit pruning to the area that grew last year. You should cut dead wood back to branches and leave no stubs. The small bead (astring) between the branch and the trunk must not be damaged.
Thinning out thick maple branches - How to do it right
If you want to remove a thick branch from an old, large maple tree, the measure requires an alternative cut. Here's how to do it in 3 steps:
- Saw the branch from the bottom to the middle at a distance of 30-50 cm from the trunk
- Now move the saw outwards by 10 cm and saw from above until the branch breaks off
- In the third step, cut the remaining branch back until just before the astring
Finally, smooth the cut with a sharp, disinfected knife.
When is tree pruning mandatory?
A maple tree develops its well-formed crown without regular pruning. In view of the low pruning tolerance, you should only prune trees and shrubs of this genus when necessary. In three cases it is still essential that you cut back a maple tree:
- After planting bare-root produce, prune all shoots by a quarter to a third
- After transplanting, compensate for the lost root mass by pruning proportionally
- Prune sick shoots down to he althy wood
Wound closure – yes or no?
Thanks to modern research results, wound closure after pruning a tree has come under criticism. Intensive field research by tree surgeons provided evidence that airtight sealing of cuts does more harm than good. The injured tissue does not heal like human skin. Rather, a layer of callus covers the wound and encapsulates the injured wood. Fresh wood, called cambium, then forms over this insulation.
Sealing with tree wax would only disrupt the natural healing process. Only after pruning a tree in autumn should larger cuts be treated to protect the valuable callus tissue from frost. For this purpose, coat the edges of the wound with tree wax or Lac Balsam.
Tip
Pruning of maple trees does not only refer to the branches and crown. Sometimes a root cut comes into focus because there is no gap to be found on the tree disk for a nice underplanting. There's nothing wrong with pruning irritating roots on a well-established maple, as long as you don't remove more than a third of the strands.
