I have a 4 year old Japanese maple that the bark is splitting from the bottom...

Asked September 22, 2019, 2:38 PM EDT

I have a 4 year old Japanese maple that the bark is splitting from the bottom half up to where there is a knot on the trunk and the tree is dying(?dead). It is located 3 feet downstream from hydrangeas that I treated with elemental sulfur and 2 of the hydrangeas have partially dead branches but the plant is still viable and thriving again now. Could this be from the sulfur or do I have another problem. I have many deer on my property.
Thanks

Livingston County Michigan trees and shrubs bark splitting

2 Responses

Hello,

This tree is severely damaged and may not survive. The crack on the trunk may have been from frost damage over the winters, especially if it is on the south or west side. Similarly it could be from sun scald. The damage underneath is such that the tree can’t move water and nutrients up and down that part of the trunk anymore.

The knot on the trunk looks like damage from pruning, or possibly a failed graft where a weeping form of the tree may have been grafted onto an upright trunk.

The sulfur should not have caused any problem, unless a chemical form of sulfur( like aluminum sulfate) was accidentally over applied.

Another issue is the stone mulch. While attractive it adds no nutrients to the soil and reflects too much heat from the sun, causing stresses on the trunk and the whole plant. Finally, the tree has been planted too deeply- the trunk should flare out at the bottom- this is called the root flare or the root collar and should be at soil level. (Picture below is an example) Mulch should not cover the root collar, it is an important way the roots receive adequate oxygen.

What you can do- if the tree seems to be leafing out each year and branches are not dying, then you may want to keep the tree. Pull the stone mulch back from the trunk and expose the root collar. Check soil moisture down 8-12 inches and keep the tree watered at the base, keeping leaves dry. Consider creating a shredded bark or wood chip mulch circle around the tree. Don’t let the mulch touch the trunk.

If you replace the tree all these recommendations apply to a new tree, too. Here is the Tree Owners Manual which explains correct planting, root collar, mulching and care.

https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5368392.pdf

To protect trunks over winter, especially on a new tree, use a tree wrap from late November through March or April. Remove it each spring, then replace again in late fall. Do this for the first 4-5 years until young bark has thickened. ( there are paper tree wraps that are tan instead of white and may be more esthetically pleasing) See the Sunscald section here-https://extension.umn.edu/planting-and-growing-guides/protecting-trees-and-shrubs-winter#sunscald-1263860

The most important thing is to keep trees watered during dry times from spring through late October. If you have any questions on this, please write us again. Thank you.

Here is the picture of a tree showing the root collar flaring out at the soil line