I live in Boise, Idaho. Last summer, I bought a Meyer lemon tree and a dwarf orange tree. I have had no problems with either during last summer, or wintering over in a hot, sunny room in the house. In the spring, just before moving them back outside, my lemon started to drop leaves. The orange has been within 2 feet of the lemon since the beginning, same watering pattern, fertilizer, sunlight, pot size, etc. It is now October and the lemon has been hanging on to a dozen leaves for the last month. They both have fruit, and blossoms, but my poor lemon is now down to just 5 leaves. They are beginning to yellow on the tips, and I am afraid for them! It is mysterious because the plant seems otherwise healthy....4 lemons and tons of new blossoms. It is almost time for me to bring them back in the house for the winter, but I don't know if the shock will kill it in this fragile state. I use a fertilizer I bought with the plants, and I use it every 3 weeks as directed. The orange is gorgeous, glossy, and bushy, but my lemon is not doing so good. Any advice?