What’s Happening to My Maple Tree?

(Question)

Hello, I have a maple tree in my backyard, in the southeast corner of the lot. It is about 8-10 years old. It gets full sun and for the last two years, since I have owned this home, has been flourishing. I water it twice a week at least. I went on vacation for three weeks and when I returned, I noticed that all of the leaves were dead or dying. I don’t see evidence of any rot on the tree. While I was gone, it was quite rainy, so I can’t imagine that it got damaged so quickly in just three weeks. Could you please assist me?

(Answer)

Thanks you for contacting the Toronto Master Gardeners about the condition of your maple tree. The pictures that you have included are somewhat helpful in determining the problem. It certainly would be distressing to find your tree in this condition after returning home, especially since it has been “flourishing” for the past couple years. However, it is most likely that the tree is suffering from leaf scorch. Drying leaves are a symptom; other leaves may become brown, curl up and fall off the tree–seems that might be the case. The cause is weather-related–due to low moisture, high temperatures and dry wind that we’ve experienced for long periods this summer in Toronto.  Even though there was a period of rain while you were away, the damage would have started before you left for three weeks. Since the leaves are the last tree part to get water, they are the first to show signs of water insufficiency.

You mention that you water it at least twice a week; for how long do you water it each time? It’s more effective to water slowly and deeply every 7-10 days so that the water reaches the root area.  The use of an organic mulch (as it seems that you have) will help to conserve soil moisture around the tree; however, a mulch is most effective in conserving ground moisture if it is at least 3-4 inches thick and spread away from the trunk of the tree. One needs to make sure that the moisture penetrates into the soil–water thoroughly, but less often.

It’s important to understand that even though the roots extend out beyond the canopy of the tree, the rain often cannot penetrate into the ground under the canopy of the tree–most rain showers do little for the ground moisture, especially after an extended dry period.

If you make sure that your tree gets consistent deep watering, it should recover somewhat for the rest of the summer season and leaf out successfully next spring.

https://dengarden.com/landscaping/Maple-Tree-Problems

https://mortonarb.org/plant-and-protect/tree-plant-care/plant-care-resources/leaf-scorch/#control