Now is the Time - February 2015 by Ken Wassum

It has been a warmer than usual winter and time is drawing short to complete repotting.  Buds are swelling on maples, elms and other deciduous trees, and once they get to a certain point it is best to wait until the next year to repot.  For this reason it is best to start repotting with deciduous trees, followed evergreens.  Chinese junipers usually the most forgiving and can be done last. 

Repotting is also a time to do some winter maintenance to your trees.  With deciduous trees you can now see branch structure.  The biggest mistake most people make is to simply trim back the ends of branches.  It is best to think about the long-term development of the tree and this often involves cutting back sections of branches that are getting too thick.  In the photos of the Korean Hornbeam below you can see that some branches were lightly pruned back to one or three buds depending on where they are on the tree.  But it also had several larger sections of branches removed that were getting too thick.  Removing these thick sections helps the tree look more and more refined, and accentuates the appearance of the trunk.  Just as the trunk should decrease in thickness as the eye follows it from the base to the top, the branches should also decrease in thickness and they flow out from the tree.

 

The Japanese white pine below received a little more drastic attention.  The two-year old needles were removed (cut – never pulled) and, like the hornbeam, branches were cut back, with heavy sections removed.   Thinning was more drastic on top and on the ends of branches where the tree is strongest.  The branch that was on the bottom right always bothered me as I thought it gave the tree a static look,  but I was reluctant to cut it off.  Last week after shortening it significantly I decided it was time to go.  When the tree is repotted in a year or two it I will rotate the tree about 15 degrees clockwise to accentuate movement in the trunk.  The next step is to wire the lower branch on the right and move it around a little more towards the front.

 

Winter work on your trees can include so much more than repotting.  For evergreens and deciduous alike there is always plenty of work to do!

Have fun!