Dear Master Gardener, I have two flowering cherry trees in front of my house...
Dear Master Gardener, I have two flowering cherry trees in front of my house that I suspect are in need of pruning. Both crowns are very large, and one tree is growing more on one side than the other, unbalancing the tree. I have looked a little around the internet and have not had much luck finding instructions for pruning my trees that I would trust. I was hoping that you could put me in touch with someone who could help me out. I have taken photos of each tree from each side, one far and one close, and was hoping that one of your master gardeners familiar with pruning cherry trees could look at the photos and give me some guidance. The attached photo is typical of both trees - one or more limbs has grown to a size that puts the tree out of balance, for example the large limb growing to the right in the photo. The other photos are available on Google Drive, and I can email links to the photos. I understand the trees should be pruned while dormant. Are they still dormant at this time of year? Can I cut such a large limb from the tree without killing the tree? Both trees have very large crowns - how do I prune them to keep the tree healthy? The unbalanced tree is beginning to show roots above ground on one side - is that due to the unbalanced condition? Thank you, Jason
Baltimore County Maryland
As long as trees are growing without health problems, little to no pruning should be done. You've identified one reason to prune--a lop-sided, off balance tree that could possibly be in danger of falling or blowing over. The very large limb to the right of the photo does look like it is exceptionally large and could be removed, but it's hard to tell exactly because of the angle we're seeing in the photo. It would be helpful if you could attach more photos in a reply (in replies, you can attach up to 3 photos) so we could get a better picture.
Yes, your trees are dormant, i.e. they are not leafed out or actively growing. For good instructions of HOW to remove a limb, please carefully read our pruning fact sheet: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG84_Pruning%20ornam... Be sure to study how a pruning cut should not remove the branch "collar."
The rule of thumb about how much of a tree can be removed at once is 1/4th of the canopy.
As for the exposed roots, it looks like the roots are exposed on the downhill side of the tree. Roots are often exposed by the slow process of erosion. You can put 1 or 2 inches of soil over the roots if you want. It doesn't seem that the roots would be pulling out of the ground on that side, since that it also the side that has the heavy large limb.
Incidentally, when you use this "Ask An Expert" feature, your questions are answered by certified horticulturalists who are employees. Master Gardeners is a volunteer organization also run out of this office, but they do not answer the phone here or email questions.
We hope to see more of your photos.
Thanks for the response. I have attached two more photos of the tree, and one photo of the roots, which are on the uphill side of the tree and show more each season. The very large limb (in "tree 2 trunk2," the one on the right with the healing cut where a small limb was previously removed) is the one that really puts the tree out of balance, as it has grown pretty long and then it branches several times. This limb is the one I would like to remove. I hope you can see it in the photo of the entire tree, "tree 2 west side." I will follow the pruning instructions you gave a link to.
I think I'll leave the other tree alone; though it's getting very big, it's not unbalanced like "tree 2" is.
Any additional thoughts would be appreciated.
Your decision to remove the one overly large branch looks like a good one. That is a very nice tree, and one we're sure you'll want to be careful to preserve. You might want to contact a tree service company (or two) which has a certified arborist (certified by the International Society of Arboriculture) and have the arborist come look at the limb. There is no charge to look at the tree, only to treat the tree. To locate a certified arborist, here is a website: http://www.mac-isa.org/ The arborist could give you an opinion on how and where to cut.
We can see that the roots are very shallow and extensive. If there was enough erosion to expose all those roots, you're probably aware of it. Another reason that trees have lots of exposed roots,however, is that the soil is compacted, i.e. densely packed together (usually there is a lot of clay in the soil.) When soil is compacted, oxygen and water cannot get down to the roots under the ground, and in order get the oxygen and water it needs, the tree's roots are forced to grow up closer to, or on, the surface. Once soil is compacted, there is not a whole lot you can do to make it better for the tree, however you can avoid walking or driving mowers on the soil when it is wet. One other thing you could do is use a core aerator on the lawn. An aerator pulls little plugs of soil out of the ground, and then you can spread an organic soil amendment (usually a composted leaf product or composted manure) over the lawn so that it fills up the holes.