How to Expand a Tree's Mulch Ring - Ask Extension
Hello-
We just had four, new 2" trees planted two years ago (Red Maple, Sugar Maple, Sweetgum, American Elm). The landscaper who planted them...
Knowledgebase
How to Expand a Tree's Mulch Ring #848151
Asked August 31, 2023, 9:27 PM EDT
Hello-
We just had four, new 2" trees planted two years ago (Red Maple, Sugar Maple, Sweetgum, American Elm). The landscaper who planted them installed a ~3ft diameter mulch ring that I have been maintaining. But since these trees have really taken off this year, I wanted to expand the mulch ring to a 6ft diameter to get closer to the drip line. I started with the Red Maple, marked and edged the new circle, but then realized how shallow the root system is!
Is there a best-practice for how to edge and remove grass & weeds without damaging the root system of the tree?
Does my Red Maple need anything extra after this accidental root pruning?
Can I expect the other three (3) trees to have shallow roots too?
Should the mulch rings be expanded, or just left at 3' diameter?
Montgomery County Maryland
Expert Response
Not to worry. You are doing a great job and there shouldn't be any lasting damage to your tree.
We are happy for your question though, and yes, expanding the ring for all your trees is a fine idea. It will keep the roots cooler and more moist, the tree will have less competition for water and nutrients from the grass, and it will help protect the trunk from accidental mower/trimmer injury.
You can smother the extra grass growing around the tree, by either scraping the grass off as you are able and/or depriving it of sunlight. Normally we caution the overuse of mulch- suggesting no more than about 3 inches, but for a short period of time you could mulch deeper on the grassy edge or even lay some cardboard and then mulch over it, removing the excess mulch/cardboard in mid-spring.
A couple of other thoughts-
~ it's been a very dry/droughty year. Keep your trees well watered throughout the fall up until the ground freezes for winter. Roots keep growing even when leaves have dropped.
~ Inspect your young trees to make sure they are not planted or mulched too deeply. You should be able to see a gentle widening or 'flare' before the trunk enters the ground. If you can't, remove mulch or soil until you can.
Christine
We are happy for your question though, and yes, expanding the ring for all your trees is a fine idea. It will keep the roots cooler and more moist, the tree will have less competition for water and nutrients from the grass, and it will help protect the trunk from accidental mower/trimmer injury.
You can smother the extra grass growing around the tree, by either scraping the grass off as you are able and/or depriving it of sunlight. Normally we caution the overuse of mulch- suggesting no more than about 3 inches, but for a short period of time you could mulch deeper on the grassy edge or even lay some cardboard and then mulch over it, removing the excess mulch/cardboard in mid-spring.
A couple of other thoughts-
~ it's been a very dry/droughty year. Keep your trees well watered throughout the fall up until the ground freezes for winter. Roots keep growing even when leaves have dropped.
~ Inspect your young trees to make sure they are not planted or mulched too deeply. You should be able to see a gentle widening or 'flare' before the trunk enters the ground. If you can't, remove mulch or soil until you can.
Christine
