HI! I have a 16 year old maple "Atrolineare', which is dying. It turns out it's not actually an Atrolineare, because it is green, not red. That said, a couple of years ago, the Linearilobum leaves seemed to be taken over by a its graft stock, in that the leaves were coming out palmatum. (I have pics.)
Last year it was bright copper red (like autumn) all summer, with more palmatum leaves. This year, it seems 99% of the Linearilobum leaves are gone, leaving dead branches. It's still mostly red this year, vs. its normal green. I tried to get a pic of both leaves on one branch, but they're just dying. I'm seeing red leaves on 2 other of my over 100 maples (mostly Japanese) and I'm scared. Any ideas what might be killing my beautiful trees? Thank you for your time.
Early fall color (reddening) of tree foliage is an indicator of stress. A stressor can be a pathogen or pest or unfavorable environmental conditions (excessive wet weather, high heat, pesticides, pollution, etc.). The unusually high amount of rainfall last year and into this spring has been stressful on many plants. Roots need oxygen and in saturated soils for too long, roots can become compromised, leading to dieback in the canopy.
Japanese maples can be tricky to grow in this area; they are susceptible to a number of problems ranging from root problems to fungal diseases. This article by our plant pathologist goes into detail about some of the common issues and the type of growing conditions in which Japanese maples do best. https://marylandgrows.umd.edu/2018/08/24/japanese-maples-in-maryland-landscapes-plant-location-care-...
Typically, when a Japanese maple has dieback like the one in your photo, all you can do is prune out the dead branches. Use a light layer of mulch at the base of the tree to help regulate soil temperature/moisture and water in dry periods to minimize moisture stress.
Thank you for your response.
I've never seen stress cause a mature, grafted tree to revert to its root stock.
Also, in this instance, the tree is in a raised bed off a slight slope and luckily drainage isn't an issue.
Trees are mulched regularly (not up against trunk).
I'll keep trying to find an answer and post here if I do.
Graft failures can occur because of genetic incompatibility, improper technique, or environmental conditions. Here is more information on why grafts sometimes fail.
Never heard of a 16 year old graft failing. I'll read, though.