My bonsai's leaves started turning yellow 6 or so weeks ago, pretty much out of the blue. She's been in the same window, receiving pretty much the same amount of water for the last 18 months. Her pot has two big holes in the bottom, so she's never sitting in water. I definitely watered her less over the winter (3-4 times per week) as opposed to the last few months when she's been watered every other day.
I was getting worried and so I ran some plant food through with her watering about three weeks ago. I thought maybe she was just hungry. Her leaves have gotten progressively yellow and feeding didn't seem to help.
There's no heater blowing on her and as far as I can tell, her environment hasn't changed. I don't see any signs of infestation under the leaves or in the moss, although the yellowing leaves have brown spots that seem to get darker and more pronounced as the leaf becomes more yellow (this could just be part of the yellowing process?).
We took her out of her pot yesterday and I gave her fresh potting soil. She's sitting on the front porch now, although I'm a little worried it's going to get a bit warm for her over the next week or so.
Do you have any ideas? Are there any bonsai doctors out there? I am so worried and sad and I just don't know what else to do. Thank you so much if you are able to help. Can you tell me what kind of tree she is?