We have 5 of these kousa clumps in the southwest part of the yard along slope behind our pool in north oakville can the bottom branches be pruned now? April 15th today. They are approximately 6 years old and have never been pruned. If not now when? Thank you in advance for your time.
Thank you for contacting Toronto Master Gardeners.
Cornus kousa are beautiful dogwoods, you are fortunate to have 5 healthy specimens.
As this tree blooms in the spring you would not prune until the flowers are finished. If there are any dead or damaged branches then they should be removed immediately. The trees may not need pruning. If they have good shape and there is good air flow through the canopy then you can just let them continue to grow. If you feel they could be thinned or there is a branch that is not following the natural shape of the tree then you may want to prune.
If you do decide to remove any branches you need to follow the branch back to where it attaches to a main stem or larger branch. It is at this point you will want to cut it. This allows the tree to maintain its natural shape while thinning the canopy and allowing more air flow through it. You should not cut too many branches off one tree at a time. If you remove too much it will stress and damage the tree. Depending on the size of the trees,you may be best advised to consult an arborist to prune off large branches.
I have attached links below for you do further reading on your tree and pruning techniques.
Good Luck.
https://hvp.osu.edu/pocketgardener/source/description/co_kousa.html