We are located in Guelph, Ontario. Zone 5b.
We planted a small, japanese maple tree in our front yard in June of this year (full sun in the morning). The leaves have begun to wilt over the last month. We have been away on vacations over the summer, so thought perhaps it was a watering issue, but have given it good drinks over the last week and no signs of recovery. Any assistance would be appreciated.
Hello! Thank you for your inquiry to Toronto Master Gardeners. Our guide to growing Japanese Maples provides information that I excerpted below. The problem might be related to some of the conditions described here, but it could also be that the plant is not sufficiently hardy in your area. I assume Guelph is Hardiness Zone 6. This is the limit of many Japanese maple cultivars. When gardeners wish to test the hardiness of a well-loved plant like the Japanese maple, it’s best to position the tree in a sheltered spot in the garden, or near the house. The best case scenario is that the tree, like all new plants, needs ongoing care while it becomes established. Don’t be discouraged by the wilting. It could be that the tree needs more water—20 minutes of a slow drip at the roots applied twice weekly. Place mulch in a donut shape at a distance of around 1 foot around the tree, taking care not to mound up soil or mulch against the trunk.
“The best soil for Japanese maples is a sandy loam with a low to medium amount of organic matter, well-drained, and well-mulched if in adverse soil conditions. Additions of acid fertilizers are needed in extreme alkaline conditions. Japanese maples have the same soil pH requirements as rhododendrons. If you amend the pH, be aware that this will be required every few years. Japanese maples should have a uniform supply of moisture. Proper water management is far more important than fertilizer or soil types. Top shaping and pruning should be started early in the tree’s life. Major pruning is done during the dormant season, corrective pruning at any other time.
Japanese maples are not often subject to serious insect infestations. Other than the usual range of insects found in landscapes, there are no major predators on these plants. Some problems are aphids, mites, moth larvae and root weevils. None of these is considered life-threatening.
This is the worst problem of maples. It can be caused by one or more of several organisms, cultural practices, climatic conditions or soil chemistry. The most serious cause of die-back is verticillium wilt. This is a fungus that enters the cambium layer, blocks the flow of nutrients within the tissues, and causes a brown streaking within the layers under the bark. New shoots, twigs, and branches will die quickly. No definitive solutions are available at this time. It is important to sterilize all pruning equipment, keep the tree healthy, and remove infected parts which are then burned. This will limit further spread.
Leaf scorch and twig burn
There may be many causes: wind burn, exposure to extremely hot sun, late spring frost, salt runoff from roadways or excessively alkaline soils, short intense drought periods, container plants in full hot sun. Usually the plant is not lost, but the appearance and vigour of the maple is damaged for that season.
This is caused by too much water, poor drainage, poor air circulation and insufficient light. Corrective action is the best remedy.”