I have a verigated maple tree that I planted about 5 years ago. This tree is very slow growing!! The tree is absolutely beautiful for the spring and first part of the summer. However, every year around mid-July, the white edge on all of the leaves turns brown and crunchy. My beautiful tree turns into an absolute eye sore in about a week. Since this has been happening since I planted the tree, I have had many opportunities to try and determine what is causing the problem. I have applied fertilizer, used pest spray to control the Japanese Beetles that love to eat it, and even set up a personalized sprinkler system for it to ensure that it receives plenty of water. I was hopeful this summer that I had finally figured the tree out- I thought maybe it just needed more water. I was wrong. Even with the water, the edges of all of the leaves has turned brown and crunchy and looks awfull! As a note, I have planted 9 other trees in my yard of various species and they are all thriving. Does anyone have any idea of what may be going on?
I thought that may have been a possible cause. But, none of my other trees have this problem. If it is sun burn, what do you do to prevent it?
Shade it with another tree or move it. Not all variegated maples will burn in sun, but some do. Here A. p. 'Sagari nishiki' and 'Ukigumo' burn the worst, while A.p. 'Oridono nishiki' and others seem fine in full sun. Not sure what maple you have there or conditions, etc., so it's hard to guess what the problem is.
The vulnerability of the variegated portions to hot sun or other stress is why these parts only are turning brown. Unless that one is not attacked by Japanese beetles, probably you have Acer platanoides 'Drummondii'. Many specimens of this cultivar are also showing some browning now even here in comparatively cool and dull (but quite dry) summer conditions of western WA. Apparently your humid and rainy eastern summers are not adequate to protect your tree on your site, something will have to be done to ameliorate the conditions, as suggested. Note that if you have future difficulties with other plants, you always want to find out what, specifically the problem is BEFORE taking corrective measures - especially those involving chemical applications (fertilizers or pesticides).
