College of Tree Knowledge

Can you name two of the biggest problems
in the landscape today?

A. drought
B. insects
C. global warming
D. winter injury
E. fungus disease
F. too much water
G. none of the above

Answer G – none of the above

Two of the biggest problems in the landscape today are planting too deep and over mulching.

Tree roots breath, there is a gaseous exchange of elements at the root system. Planting too deep or applying too much mulch can cause several problems.

1. Suffocates roots and causes tree mortality often within six months.

2. Roots will grow up for air further enhanced by moisture in the “mulch volcano” producing a secondary root system that encircles the main stem ultimately strangling the plant. Very often it can take up to ten to twelve years to actually strangle itself.

3. The tree trunk is a live part of the tree that breaths as well, excessive soil or mulch against the trunk will slow down or stop conduction of water and nutrients from the roots to the leaves.

4. When roots come up into the “mulch volcano” they are the first to be burnt by winter frost causing winter kill and the first to be dried out during drought conditions causing what we call the, double whammy!


1. Locate the root flare when planting. This is the transition zone between the main stem and the root system, it should be exposed. If your tree goes into the ground like a telephone pole it is a sure sign there is a problem.

2. Pay close attention to the way that trees occur naturally with a well defined root flare.

3. When plants are installed at the correct depth the roots extend down first then horizontally with the fibrous roots roughly at the drip edge of the tree. Roots go down first naturally because the subsoil is cooler and damper in the summer months and actually a bit warmer during the winter months.

4. Remove excessive mulch, a two inch layer is plenty. Periodically remove mulch in plant beds before installing new mulch. If you still have a doubt about planting depths or mulch we are happy to help. We estimate that as many as 80% of plants installed are either planted too deep or are being killed by excessive mulch.

5. Always remember, very often insects and disease problems are secondary to poor health. More water and fertilizer will not correct the problems caused by improper planting depth or excessive mulch.

Finished product, compressor and truck.

Mulch volcano.

Locating root flare with air spade, excavating soil with compressed air.

This tree has produced a secondary root system, a result of over mulching or planting too deep. These roots will girdle and kill the tree over several years.

If this problem is diagnosed early enough, girdling roots can be pruned away and the tree root flare can be exposed again.

During the last step in our remedial treatment we apply a root enhancing fertilizer at the drip edge of the tree to encourage root growth away from the root flare.

Bartlett Tree Experts

Matthew R. Foti Tree Service is proud to be a division of Bartlett Tree Experts, and our staff now has the backing of an international tree-care company and tree research laboratory to help continue providing excellent tree service and shrub care in the Eastern Massachusetts area. View a complete list of professional tree services offered by Bartlett.