I have had a Japanese Maple for 10yrs but for the past 2yrs it has had die back to one side-any ideas?

Answer 1

Several actually.

Have you checked for damage along the trunk? Lawnmoweritis is a common cause of onesided dieback.

Have you checked for borer holes along the trunk or out on the affected limbs? Are there soft spots or discolored spots along the trunk? A canker disease might be in play.

The next ideas are below ground.

One is a strangle root. When woody plants remain in their pots too long in the nursery......even back at the production nursery, not the sales nursery......the roots kink. When transplanted to a larger pot, the root doesn't unkink....it's not a spring. So as the root system grows and the tree grows and the trunk grows, the roots can actually wrap around a portion of the ever widening trunk, cutting off the water/nutrient/and food transport. The cure is to cut the strangling root........if it won't kill the plant by doing so or cause it to fall over.

Same idea, but it could be a piece of twine from the burlap the tree roots may have been contained in. The twine doesn't rot and can get embedded in the trunk. Or a wire basket used to hold the roots could also be crimping the root below.

Finally something wrong with the soil on that side. Was a weed killer applied on that side........even away from the tree? Could the roots have gotten into some underground toxin? Somebody pour gasoline on the soil? Is the soil overly compacted on that side?

Lots of ideas, but you need to be the detective.

Answer 2

Single stem or one side dieback is diagnostic for verticillium wilt. This is a serious fungal disease and it often hits maples among several other woody ornamental plants.
The disease can hit one stem at a time, or one side of a tree. Other symptoms of Verticillium wilt may include: marginal browning and scorch of leaves, abnormally large seed crops, small leaves, stunting, poor annual growth, and sparse foliage.
The way to determine the presence of the fungus in the field is to cut a small dead branch off the tree. Cut it at a long angle to the expose as much pith as possible. Look to the cambium and xylem layers just under the bark. If they show visible streaks or spots, generally grayish green, to olive or darker blackish green in one or more growth rings it is likely you have the fungus in this branch but a it should be verified in a lab.
If it is only this one branch try adding ammonium sulfate fertilizer but severely infected trees must be removed.
Cornell labs say " Wilt severity is increased by "high- nitrogen" fertilization and reduced by the use of "balanced" fertilizers having analysis such as 10-10-10. Fertilize as necessary to maintain N-P-K balance in the soil (i.e. supplies of available elemental N, P, and K having roughly a 2:1:2 ratio)."
The fungus enters through the roots and proceeds up water channels blocking them so the tree becomes more susceptible to heat and drought stress. It needs a steady supply of water to support growth. Sometime a large healthy tree will grow faster than the disease kills it if other stress factors are controlled.http://counties.cce.cornell.edu/suffolk/grownet/tree-disease/vertwilt.html

Answer 3

We had one to die only to find out someone kept hitting it with the lawnmower! At the time the Japanese Maple was worth a little over $1000!