|
Pruning
Overview
Maples can be pruned 7 to 9 months out of the year. There are many different philosophies about when to prune and even how to prune. You will often hear that maples should be pruned in late winter and this often refers to large pruning cuts like branch and limb removal. Some people believe that late winter right before bud break is a good time and others feel that anytime from early summer to fall is a good time. There really is no great answer, but if we consider how the plant might respond or the consequences of out pruning then we can use some logic to arrive at a useable plan.
Winter Pruning
Pruning in winter speaks our ability to see the tree without leaves and to better understand its shape and form. This is a good time of year to remove dead wood and twigs. It is also a good time to prune dissectums or laceleaf maples since they are very dense and we may not be able to understand their shape with leaves in the way. You can prune just before bud-swell or as it starts. Once the buds begin to break it would be better to wait until the spring flush of growth is finished. The other idea behind pruning this time of year is that we can remove wood before the tree devotes energy to leafing on undesirable branches and the subsequent growth to follow. That makes sense, but the tree also has energy stored in the limbs and buds--not nearly to the degree it stores in the roots--and we believe it can be detrimental to remove a great deal of wood in winter. The other consequence is that winter pruning cuts can be slow to heal and once the sap starts flowing near bud-swell the wounds will weep some and heal more slowly providing opportunity for disease to enter the plant. If you are to make large pruning cuts in winter using a wound paste (lanolin or wax-based) to seal the wound might be a good idea.
Early Summer Pruning
Pruning this time of year refers to pruning after the spring flush of growth is finished and as it is hardening off. This is usually in early June in the western United States. This arguably the best time of year to prune in many parts of the country because the pruning cuts heal quickly and the plant can be stimulated to produce some "redirected" growth. By this we mean that generally maples responds by producing growth opposite the pruning cut and when the growing season is long enough pruning in early summer allows you to see this growth before fall and get a head start on next season. Because pruning always creates some stress it is good to prune lightly. Since maples rarely need heavy corrective pruning, it is usually not a problem to prune lightly. This light pruning is often called "pinching" when it pertains to new shoots and will be discussed below.
Late Summer and Fall Pruning
Pruning this time of year should really be limited to pinching or shaping any new growth that has developed as a result of summer growth. If the plant has produced a very long shoot now would be a good time to partially pinch it back. If there is a little light grooming you can do this now also. Pruning cuts still heal very quickly but it will be too late to see any new growth. One argument to prune minimally this time of year is that in areas with long growing seasons (into November) moderate pruning can still stimulate some regrowth that may not harden before winter.
How to Prune
Pruning maples is like pruning most other wood plants. You want to use sharp pruning shears or clippers and sterilize them from time to time. If you are pruning diseased wood you should sterilize more frequently. When removing branches from the trunk you should make a nearly flush cut just outside of the branch collar (the wood calloused ring located at the branch-trunk union). When removing twigs and trimming or shortening branches you should prune back to the next desirable bud-pair or the next side branch leaving about 1/4" of wood so that plant can seal off the wound.
Pinching refers to shortening new growth from the current season. It is simply a type of shaping where undesirable or lengthy growth is clipped back to a desirable length but not removed entirely. Say you have new shoot developing in a desirable location but it is becoming far to long. Removing 1/3 to 1/2 of the new shoot length would be pinching. This is a great way to stay on top of your young plants and it has little impact on overly plant health. Maples can produce overly zealous leggy growth and pruning is often needed to keep the "natural" shape of the plant. In some cases it is simply the growth habit of the maple and other times it is an overly fertile culture (high-nutrient potting mix or too much fertilizer) that causes this growth. If you are seeing a lot of it and are not sure if the plant is known to grow like this or if you are fertilizing too much send us and e-mail and ask. We will be glad to help. If you are using more than just a little nitrogen it may very well be your cultural practices.
For information on pruning young maples and shaping their future growth, see the FAQ: Should we Prune Young Maples (Coming Soon!)
|
