Brown leaves on Japanese maple

Asked August 1, 2019, 11:21 AM EDT

I have some branches that the leaves are turning brown. No chemicals used. The tree appears healthy and no sign of bugs. Shall i fertilize it with hollytone and cut out die back branches or is this because of little rain? How do i fix this? Tree about 10 ft tall and perhaps 5 to 6 yrs old. Thank you

Frederick County Maryland abiotic issues japanese maple trees browning leaves on japanese maple

1 Response

The leaf browning and dieback suggests a pretty stressed tree.
We can't say exactly why from afar, but most problems with Japanese maples tend to be related to environmental or cultural conditions, like heat, drought or planting/mulching too deeply.
Here is a blog post from our plant pathologist that discusses some of this:
https://marylandgrows.umd.edu/2018/08/24/japanese-maples-in-maryland-landscapes-plant-location-care-...
We can't see the very bottom of the tree where it goes into the ground but you should be able to see a flare or gentle widening of the trunk before it enters the soil. It should not go straight in like a telephone pole, and if it does it suggests that it is either planted or mulched too deeply which can slowly kill a tree over time.
Here is our page which covers these types of problems. Click on the tiles/description to read more about that and what to do:
https://extension.umd.edu/hgic/topics/cultural-and-environmental-0

We would not recommend fertilizing. Fertilizer is not medicine and could possibly stress the plant further. Make sure it gets deep watering if we don't get at least an inch of rain a week. Dead wood can be trimmed out at any time.

Though less likely, there is a Japanese Maple Scale, which is a sucking insect that is easy to overlook as they look like tiny (1/8") white, elongated, still dots on the bark.
Here is a page about armored scale: https://extension.umd.edu/hgic/topics/armored-hard-scale-trees-and-shrubs

Certainly if the tree is important to you your best bet is to have a tree health expert, called a certified arborist come and do an on-site evaluation of the tree and recommend treatment. Certified arborists are not just tree cutters but are credentialed by the International Society of Arboriculture. Most larger tree companies have one on staff or you can search for one at www.treesaregood.org



Christine