I will assume you're keeping it indoors, and you can't, it's a deciduous, cold hardy tree that needs to be outside for life, to gradually acclimate to the winter over the fall, and reverse that in spring, with below freezing temps in between. Second, sounds like you might have two problems (if not more), one would be dryness (no humidity tray?) and the other possible spider mites. A third (from the white powder sound of things) would be powdery mildew from soil being kept soggy all the time and probably a bad mix to begin with - peaty potting soil that holds water all the time, no grit in there for fast drainage, and likely watering way too often. You'll have to judge which of these is going on and treat accordingly. Mites need Safer's Insecticidal Soap spray, powdery mildew needs a proper mix, less frequent watering and great air circulation, and lack of humidity needs a proper tray of stones and water under the pot, with the water never high enough to touch the pot itself. Do some research before you get another tree please.

Thank you for your insight. I will indeed look into the things you mentioned. The person I bought it from said nothing about keeping it outdoors - I didn't even realize there was more research to do. Now I know!

Something just occurred to me - could you possibly have a 'Brush cherry" (Eugenia)? That's not a regular 'Prunus' (hardy fruit tree that lives outdoors) but a tropical/semitropical that DOES belong inside anywhere north of Florida.

I just checked and it is an Australian Brush Cherry. I live in Wisconsin. So it does belong inside? Also, do places like Steins carry the Safer's Insecticide Soap?

Thank you!

Inside for sure! I have no idea what Stein's is, but most garden ctres or nurseries should (and follow label directions). But you shouldn't just spray a plant unless you know what's wrong... if you have seen tiny webs between branches and leaf stems, or even seen the tiny mites, that's different, but if you haven't, you shouldn't.

No, there are no webs. Just the leaves drying out while the base of the trunk is turning black. I don't understand why the leaves are dry while I'm still watering it... I turned the ceiling fan on in the room it's in to provide more circulation and maybe dry out the base of the trunk. The moss at the base was white but that seems to be clearing up a little. There is a little bit of white powder on the leaves (not webs). I suspected a problem with our water initially. We had hard water when I got the tree a year ago and it didn't seem to bother it. We got a water softener over the summer and that didn't seem to be a problem, either, for quite a while. I started using bottled water, but that doesn't seem to be helping. When I suspected a water problem, I watered it a little more (with bottled water) than usual to try and reverse the leaf drying. I supposed that could have caused the soggy moss and possible mildew? But the leaves are still drying out! Argh. Thank you for your help.

You may want to make sure the soil is dry before continuing to water. I have done some thinking and I thikn you might have a case of root rot. Root rot decreases the ability of the plant to take in water and slows down the time it takes for the soil to dry. An indication of root rot in bonsai occurs when a plant wilts and the soil remains wet. You may want to look up some additional information on this condition in order to determine if it is what your tree is going through.

Thank you - that makes sense. I does seem like it's taking forever for it to dry and the leaves still aren't getting what they need. I'll look into it.