Q: My red acer tree started going into leaf then the leaves dried up and died. Will it come back next year? PS, West Midlands, England
A: The Acer genus is a large, diverse and geographically widespread one, that contains more than 130 different species of trees and shrubs.
Along with well-known kinds such as the wild sycamore (Acer pseudoplatanus), the paperbark maple (Acer griseum) and the snakebark maple (Acer davidii), it incudes what are commonly known as Japanese acers or Japanese maples (Acer palmatum), a group of small trees/shrubs prized by gardeners for their very handsome, often finely cut, colourful foliage and wonderful autumn colour.
Based on your description, I think it’s probably a variety of this Japanese acer that you’re having a problem with. A slow-growing, deciduous species, numerous garden-worthy cultivars can be found growing in gardens all over northern Europe, the US and many parts of Asia . A few well-known examples include the red-purple leaved Acer palmatum ‘Bloodgood’; Ace palmatum ‘Garnet’; Acer palmatum ‘Osakazuki’; and Acer ‘Katsura’
Although it’s hardy, the Japanese acer’s greatest weak spot is that it can suffer from leaf-burn if it’s not given a sheltered, shady spot with protection from late spring frosts and cold winds or from prolonged intense sunshine. So it’s not unusual to see the young foliage being seared by a sudden cold snap. Or to see a Japanese acer that has been planted in a dry, south-facing spot where it’s in the constant glare of hot summer sunshine looking very miserable. The prolonged drought and sustained high temperatures of the summer of 2022 also wouldn’t have been at all to your tree’s liking, especially if it’s a young specimen that hasn’t yet developed a robust root system.
Will it recover? Very possibly. Trees are impressively resilient and often do bounce back from the kind of damage you’ve described. But not always.
So the first thing I’d advise is to find out whether your tree has completely given up the ghost or instead just suffered a serious check to its growth. To do this, gently scratch away the outer skin of the bark. If the layer of plant tissue underneath (the cambium) is green, then that’s a very good sign. But if there’s no sign of any green tissue and the branches are brittle and dry, then it’s not looking good. Even so, bide your time before making a final diagnosis as trees that seem as dead as a dodo can sometimes eventually start to produce new growth.
Also take a good, hard look at your Japanese acer’s growing conditions. Does it have what it needs to flourish, which is a cool, dark, fertile, crumbly, moist but free-draining neutral or slightly acid soil in a sheltered, partially shaded spot? Mulching around the base with a 5cm layer of organic matter at this time of the year will help. But if it continues to struggle, then consider transplanting it to a more suitable spot in mid-autumn.