Hello,

Many of the same problems found with Japanese maples outdoors can also be seen with those grown indoors. The first thing to do is to check the leaves of the tree, top, and underside, to see if there are any insects that are making their home on the leaves. It may be aphids, or spider mites or whiteflies. If you see any, then you must treat. The first choice would be insecticidal soap which will clear the insects and not damage the tree. If the tree is near other plants, check those also since these pests can travel and reinfect the tree.

Barring an insect, the next thing is to check the size of the container the tree is in. Generally, the container should have a diameter of about a sixth to a quarter of the final tree height. In addition, it is advisable to use clay pots instead of plastic vessels. Plastic pots heat up rapidly when they are in the sun while clay pots have better cooling due to evaporation. However, plants must be watered more frequently in clay pots due to this evaporation.

The depth of the container should be at least one and a half times the size of the root ball. IN the container should be a layer of several inches of clay granules, or coarse gravel. On top of the gravel, put some soil. The plant should then be put in and the container filled with soil to about 1 inch below the edge. Press the soil down lightly and water well. If the dimension of the pot you have the plant in do not match these, then I would recommend unpotting and repotting the tree.

Acer palmatum prefers sunny and very light half-shaded as well as wind- and rain-protected spots. Japanese maple is highly susceptible to leaf scorch, a noninfectious condition that results in dead areas around the leaf margins or between the leaf veins. Scorch is most commonly caused by weather factors such as hot, drying winds, excessive sunlight and high temperatures. If your home is very warm in the summer, particularly on these 90-degree days and if the south facing window lights the tree most of the day, then the problem could be leaf scorch. Partial sunlight with an eastern exposure is generally best for Japanese maples, because western sun can become too hot. Foliage is susceptible to leaf scorch or sunburn in the summer unless trees receive afternoon shade or are heavily watered in dry weather.

Japanese maples do not like waterlogging. If this is a particularly young and freshly planted specimen, it will need a lot of water. One reason for this is that these trees are flat-rooted and therefore do not reach moisture from deep soil layers. This means that they cannot adequately supply themselves with the precious water, especially in summer. Japanese maples need to be watered regularly and particularly in warm, dry weather you must supply them with plenty of water. Older specimens do not require as much water.

Here are things to look for to see if you are over or under watering:

Signs of Underwatering Trees

• Wilted or curling leaves that may turn brown at the tips or edge

• Off-color and undersized leaves, leaf scorch or yellowing leaves

Signs of Overwatering Trees

• The area around the tree is constantly wet
• New growth withers before it’s fully grown or becomes light green or yellow
• Leaves appear green but are fragile and break easily

In both cases, the trees can look eerily similar. There are two ways you can determine if your tree needs water.

1. Quick and easy check: Stick a long screwdriver into the soil below your tree. If that’s hard to do, your tree needs more water.
2. Precise-as-can-be check: Below your tree, dig 6-8 inches deep and grab a handful of soil. Your soil should be cool and moist. If it’s sopping wet, you’re overwatering. If your soil isn’t drenched or sandy, roll into a ball. If it crumbles, your tree needs more water.

How to Fix or Save Overwatered Tree

If your tree has too much water, it’s struggling to breathe. That excess water commandeers spots air pockets previously held. So, your tree roots are getting too much water and not enough oxygen. That’s a double whammy that could lead to root rot, fungi or long-term tree stress.

Here’s how to fix an overwatered tree:

1. Stop. Don’t water your tree for a week or two. Before watering again, do the screwdriver test mentioned above. Only water your tree when it needs it.

I do have a few questions for you that I can’t determine from the picture. What type of soil is the tree planted in? Is this a transplant from outside or did you purchase it specifically for indoors? Does the pot it is in have a drainage hole on the bottom?

Most or all the problems can be fixed with some minor adjustments to the pot, light requirements, and watering of the tree.

I hope this helps.