islandmanmitch: The tree was purchased last year as 2/3 years old. It has been watered daily and has excellent drainage. There are temperature changes--never below 50F and never above 90F, though. The tree looks healthy with lots of dark green leaves. There was, however, some yellowing and loss of older leaves over the winter. Any ideas?

a tree grown from seed will take years to flower and produce fruit, it needs to grow the right number of leaf nodes before it matures the time taken depends on exact conditions , fertiliser etc You need to use a purpose made citrus fertiliser, there are usualy winter and summer formulas, they have trace elements needed to give the nutrition neded to grow fruit at the correct times of year.

Cece. I'm not sure your lemon has insects..the holes are pretty large for most plant bugs, at least bugs I'm familiar with. What state are you in? And what state was your tree purchased from? I'm in IL, and during summer when citrus go outdoors, flying bugs come fluttering by..every so often, they nibble leaves, but by autumn all signs of insects are gone. The bad thing is they leave holes, the good thing is bugs die in days, and do not linger and kill like plant pests. To be on the safe side, inspect for bugs. Scale, Mealy, Spider Mite, Aphids, Leaf Miner..I'm not sure I covered them all, but those mentioned are insects to worry about. Normally, when insects attack, they leave signs. Yellow and/or sticky leaves, webbing, brown or white bumps, white cottony patches. I notice most rips are on the edges of leaves..Is it possible something is rubbing up against your tree? Human or animal? By the size of the tree, it'd have to be one animal..When a leaf rips it commonly browns. For starters, hose off your lemon..if you have a sprayer, add a 2-4 drops of liquid dish soap. (Not Dawn) But before spraying, check for signs of pests. If you spot any signs of plant insects, you can treat according to bug. As for flowering/fruiting, when a plant is stressed, it sometimes halts production..Actually, until you find out what's causing the problem, lack of fruits might be best. Flowering/fruiting takes energy. Toni

Dear Sara, Though I have only had my fruit tree for a few months, I have experienced the joy and disappointment on care for .......a PLANT! Don't know why, but want this one to do well. I too had this sticky white stuff. Here in Seattle, I keep my plant 50% of the time indoors, and 50% out on my southern exposed deck. After reading and inspection, I have discovered that my plant has scale, a type of bug infestation that can present. These insects are very small (my the size of a small bead) and they feed off the plant. They look like small pill (potato) bugs and move very slowly. Subsequently, their poo is the white, sticky substance that is deposited on the stems and undersides of leaves. I read this material can attract other insects (ants) but is not toxic for pets. I was able to catch it early, and washed the plant well. Then, I sprayed it with a combination of Neem oil and diswashing liquid solution (you can buy various preparations) and after a couple of days, washed again. Upon further inspection, I only saw 1 bug that I happily squished!! Must periodically inspect and occasionally wash. I don't know if that is what you're experiencing, but if so, it is much easier to treat when infestation is new (vs established). Good Luck!!