It’s totally normal for your Japanese Maple (*Acer japonicum*) to be bare by late fall, but if your tree starts dropping leaves earlier in the season, it’s definitely trying to tell you something. Don’t panic, though! Here’s how to play detective, find the root of the problem, and get your tree back on track.
Is waterlogging causing your Japanese Maple to lose its leaves?
If you notice the tips of the leaves turning brown, drying out, and then falling off, your tree is likely struggling with its water supply. This can be caused by either extreme drought or waterlogging (soggy feet). The best way to check is the “finger test”: grab a handful of soil and feel the moisture level. If it’s bone dry, give it a good soak immediately. However, if the soil is swampy and your tree is suffering from waterlogging, follow these steps:
- Dig up smaller trees or shrubs carefully.
- Prune away any mushy or rotten roots.
- Replant the tree in fresh, well-draining soil.
Is the location the reason your Japanese Maple is dropping leaves?
Take a look at where your tree is sitting. Is it getting a “sunburn,” or is the soil too compacted? Intense midday sun can literally scorch the leaves, and if you don’t move it or provide shade, the tree will eventually drop its foliage to protect itself. Compacted soil is another common culprit; if the ground is too hard, the roots can’t soak up the nutrients they need. This often happens if a container-grown tree has outgrown its pot and become root-bound.
Are pests to blame for the leaf loss?
A nasty aphid infestation can also leave your Japanese Maple looking a bit naked. You’ll usually notice a sticky substance (honeydew) coating the leaves first. This residue blocks photosynthesis and attracts other pests, eventually causing the tree to drop its leaves. You can stop them in their tracks with this simple remedy:
- Mix up a solution of water and a little bit of insecticidal soap (or mild dish soap).
- Spray the tree thoroughly several times until the pests are gone.
Is Verticillium wilt causing the leaf drop?
If your Japanese Maple is losing leaves early and you see several dead branches or “dieback,” you might be dealing with the dreaded Verticillium wilt. This is a fungal disease that clogs the tree’s vascular system. It’s important to act fast: prune out the affected branches well into the healthy wood. For larger cuts, use a wound sealer from your local garden center to help the tree heal and prevent further infection.
Pro Tip: Choose a sheltered spot!
When planting, try to find a location that’s protected from the wind. Cold drafts or late frosts can damage delicate new growth or weaken the tree so much that it struggles to leaf out at all in the spring. A little protection goes a long way!