Hello,

Your Japanese maple appears to be (Acer palmatum var. dissectum). Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=241794&isprofile=0&

Japanese maples are susceptible to several diseases including leaf blight, leaf scorch, verticillium wilt and attacks by aphids and scales. All of these may lead to browning of the leaves. Root damage also can cause browning of the leaves. The trees prefer to be situated in a spot that is out of direct afternoon sunlight and drying winds. They require moist well-drained soil.

It would appear from the pictures that your tree has leaf scorch. Leaf scorch can be caused by too little water, hot afternoon suns, too much fertilizer and damaged roots. The most common cause though is too little water.

The soil should be evenly moist. Automatic sprinkler systems are generally set to water lawns and do not provide enough water for other plantings. Trees require about 1 inch of water a week, supplied either by Mother Nature or a hose. You can measure how much water the tree is receiving by sinking a tuna fish can into the soil by the root ball of the tree and checking it to see how much water has fallen in the area. You can monitor the soil moisture by sticking your middle finger into the soil up to the middle joint. If the soil is cool and moist, the tree has enough water. If it is dry and hard, the tree needs more water. Spreading 2 inches of organic mulch around the tree (ensure that it is not up against the trunk because it will rot it) will help keep the soil moist.

It is possible that damaged roots may be preventing the tree from taking up adequate amounts of water. You can check the roots by carefully digging around the plant to assess them. Healthy roots are plump, not shriveled.

For a second opinion on the cause of the problem, you can consult the MSU Extension’s Plant and Pest Diagnostic Lab. To learn how to submit a sample and/or photo, go to: https://www.canr.msu.edu/pestid/

You can also have the tree assessed by a certified arborist. To find one in your area, go to www.treesaregood.org, the website of the International Society of Arboriculture.

Thank you for contacting Ask Extension.