Too much around tree can kill it
Q. My dogwood is dying. I know I should not have built a flower bed around it. One stem is dead and some leaves are small and wilting. What should I do now?
Anonymous from Canfield
A. The tree could be suffering from stem girdling roots or could have a canker. While keeping a mulched area over the root zone of a dogwood is very important, too much mulch and added soil can stress the tree and cause many issues.
Dogwood trees are understory trees, meaning they grow under the tall trees in our forests. Thus, keeping grass competition down with mulch can be an effective way to reduce tree stress.
In general, this tree has been stressed from the added soil around the trunk and from the plants added around its trunk. The mulch, soil and plants need to be removed from the base of the tree down to the trunk flare. The trunk flare is the bottom of the trunk that begins to widen. This is the base of the tree that should be above ground.
There may be stem girdling roots around the base of the tree. Roots are stronger, and can strangle the tree trunk. Another possible issue could be a canker. A canker is usually identified as a sunken spot, usually dark in color. If it is a canker of the main stem, the tree might not be able to be saved.
While it may be too late for this tree, this person can start by removing the excess soil and mulch. Then, the dead stem can be cut out. There are some details of cankers and other dogwood diseases at: http://go.osu.edu/dogwooddisease.
Many gardeners like to enhance the landscape with flower beds around trees. This is not a good idea, as the plants are competition for both water and nutrients that are needed by the tree. Some trees are suited for plantings under them, just not right up to the trunk. When preparing beds or planting around trees, it is important not to make a raised bed, and to stay back away from the trunk.
To learn more about best practices when planting flowers, ground covers and more around trees, check out this factsheet from Nebraska: http://go.osu.edu/undertrees.
Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Call the office plant and pest clinic at 330-533-5538 to submit your questions. Regular clinic hours are 9 a.m. to noon Mondays and Thursdays.