Hard leaves

I was just wondering if someone has any clue why the leaves on my carmona retusa gets all hard and falls off? They are not turning black or yellow. The tree is in my windowsill. It doesn't get as much sun as I wants it to, and its been wet for a bit, so do you think it could be over-watering?

Maybe overwatering AND not enough light.

The correct botanical name of your tree is Ehretia microphylla. Plants always grow better when they are properly labeled. LOL
From my limited experience and reading of Fukien tea, here is what I've learned. This is probably not a species for windowsill growing. Do you have a fluorescent lamp? This tree needs to be outdoors for the summer, in full sun, & right under a fluorescent light for the winter. My Fukien tea did just as well in one setting as the other.
It likes frequent watering, but demands good drainage. You should probably repot it in a loose bonsai mix. It loses most of its leaves from repotting shock, but they come back in a few weeks.
It grows slowly. Backbudding is slow and temperamental.
Don't pay any attention to those people from the tropics who are laughing at us with their giant yamadori. At least we can grow little Fukien teas and have tiny white flowers while the snow is flying.
Iris

If it is a Fukien Tea your talking about I would suggest letting it dry out a bit. The Bonsai Im holding is a a Tea that Ive had for about 7 years now. I usally have a large leave drop when I move it from outside to indoors. I thinks this is probably because new leafs are being generated to except the new light conditions. I have only had hard leaves once. They were on a lower branch in the middle of winter and I lost a lower branch. It turned out in spring when I repotted, it was root bound. Gave a larger pot and is now thriving and producing small red berries. Ive also found that a good humidity tray is a must for Fukien Tea. I also mist it with water daily and when needed neem oil. Be careful of white fly indoors.
Hope this helps.
Abe

Eastern, where do you keep your tree during the winter? What is the average temperature & humidity? What evidence do you have that the humidity tray makes a difference? Have you checked the humidity with & without? I assume that zaftig specimen in the picture is your Ehretia.
Iris

I usally bring in my Tea when the night temperatures drop below 45 degrees. I keep it in my basement, along with my other tropicals it usally 65 degrees. I have a grow light on a timer for about 12 hours a day. There is also a small window (south side of house). The humidity tray comment is just from personal preferance. I use Humidi-Grow trays they are very nice www.humidigrow.com . I keep them about half full of water and it seems to keep them healthy. I found when I dont use a Humidity Tray indoors they tend to dry out faster.
Abe

www.humidigrow.com

Thanks for the replies. I was away for a bit because my computer doesnt work anymore..