After that nice shock of cold weather we received last month, I am sure that most of your trees are now solidly in a dormant state. So the question becomes, what do I do now that my trees are happily sleeping away? First of all, our trees are dormant, just like a volcano. That means that although we don’t see anything going on up on the surface, there is activity down below, and in the tree. Things have slowed way down and there is no active growth above the surface of the soil, but many cold hardy trees are still working away, albeit slowly, on root development, etc... The roots of conifers are still active, bringing moisture up into the tree after winter winds have swept it all away. So we still need to monitor the water uptake in our trees.
Let’s take a look at where that leaves us. Now that the trees are dormant, that means that they will have limited means of repairing any damage inflicted by pruning, styling and wiring. That does not exclude these activities, it just means that we need to be careful of what tasks we are doing, and more importantly, to what degree. Winter used to be the time that I styled all of my conifers, at least the few that I had time for. I would do large styling bends and complete wiring jobs. I am taking a more cautious approach these days, or at least one that is better informed. I save heavy bending for the times when the trees have the best chance to recover. That means that I can’t always do everything in one go. I may have to wait six months, but I will be ahead two years from now because the tree won’t have slowed down at all. So the first rule of any work is to have a healthy, strong tree. This is the first year that I really concentrated on my fall fertilizing and it has done wonders. All of my trees are healthier and ready to take on winter, and any work that I choose to do.
Let’s start with the deciduous trees. Their metabolism has really slowed down, so we want to be cautious with pruning and any wiring. The obvious advantage we have right now is that all the leaves are gone, so that we can see the structure of the tree. If you have a species that has not dropped them yet, remove them. The sudden drop in temperature that we had last month meant that many trees did not go through the normal abscission process for leaf drop going into dormancy. The leaves merely withered up. Those trees might be especially susceptible to tip die back, since they didn’t have sufficient time to harden off before the cold.
That is also the reason that when I do any pruning this time of year, I tend to leave two extra buds past what I really want come springtime. This is my safety valve. Extra buds AND live tissue to keep sap flowing to the buds I really want. If you have trees that you let grow freely to gain strength, now is a great time to prune them back. That will allow the tree to put more strength into the buds closer to the trunk. Remember, the buds at the tip, or farthest from the trunk, tend to be the strongest and hinder the growth and strength of those close to the trunk. Leave more buds on weaker branches, and cut back strong ones harder.
On more refined trees, be sure to prune to the silhouette that you are looking for. That means that you may not be counting buds, but rather looking at lengths of branches. You mayleave some small ones longer, or cut out heavier branches to lighten and refine the branch line. I know from experience that I can cut my beeches back to just one bud and they will be fine over the winter, they eat up the cold, just like crabapples, quince, and honeysuckle. Other species are more tender. Look at the size of twigs. Zelkova and elm can be really fine and tend to be warmer area species, so you must leave more buds. Err on the side of caution and recut just before spring growth.
If you are looking for a strong back budding, this is the wrong time of year for a drastic cut. If you do it now, when the tree’s energy is receding, your chances of back budding are diminished greatly. This task is better left for April, May, June when the tree is cranking on all cylinders and able to perform as desired.
If you have decandled, defoliated, or cut back heavily any tree during the summer, whether deciduous or conifer, now is the time to go through and make shoot selections down to just two branches in any one spot. Remove shoots that are growing straight up or down. That will allow light to get into the interior and strengthen those back buds that you worked so hard to create. You can now reroute the strength to where it is needed.
It’s a good idea to leave heavy pruning to late spring, or during the growing season for the same reason. Ever wonder why cuts don’t seam to callus over? That may be a reason. The edge of the cut dies back before the growing season starts.
Conifers are a little bit different story. These guys are still growing and metabolizing. Some more than others. High mountain collected species may still have some root growth going on. Others are more tender, like Japanese Black Pine. We really do get cold enough to put them in jeopardy. I have had great luck leaving all of the foliage intact on my JBP throughout the winter, then pulling needles to thin it out in the late spring before growth. The extra foliage helps power it through the winter. Think of how this might apply to your other trees.
This is a great time for wiring as long as you are not doing really heavy bending. Heavy means that you are cracking tissue, using lots of raffia, etc… It’s all possible if you have a way to protect the tree from freezing until spring growth. I don’t, so I am a bit more cautious. Water can get in the cracks and freeze and separate tissue. Also, the trees ability to move nutrients up to the damage site for repair and for winter hardiness is impaired. This work is generally done at times when the tree either has time to recover before winter – like September, October, or late spring when it is coming out of dormancy.
Different species are able to withstand styling at different times. More than we can talk about now for winter. This is not at all to stop you from working. Just be more cautious. If we can time things right, then the tree never skips a beat and we are much farther in the long run. You can generally do all kinds of styling and wiring and most folks will not be pushing their trees as hard as what we are talking about here. Those tend to be collected trees that have not been yet styled. If your tree has already been previously styled, it is doubtful that you will be putting much stress on the tree unless you are eliminating major branches or making a drastic style change.
I hope this helps you in your work through the winter. Be sure to snap a photo or two and send them to Peter for inclusion in the newsletter. Better yet, do a little write up on your experience.