I have a lemon tree that is 10 years old and seems to have suddenly died. The leaves are brown and hanging down. There is still plenty of fruit on the plant.

When it comes to your lemon tree, you want yellow fruit, not yellow leaves. If you're dealing with the latter, micronutrient deficiencies may be to blame.

Q: My Meyer lemon at home -- planted in the ground -- looks as if it is dying. Its leaves are turning yellow and withering. I suspect root rot from too much water, but I don't know. The same ...

Once temperatures rise above 103 degrees the lemon tree will stop growing, or photosynthesizing, causing it to go somewhat dormant. If the heat lasts for very long it can cause the tree to drop fruit.