Improved Meyer Lemon TreeCitrus unshiu Absolutely the hardiest of all dwarf lemon trees, Improved Meyer will withstand temperatures as low as 32F for very short periods. It is also quite prolific producing medium sized, 3 inch, brilliant yellow fruit that turn yellowish orange as they mature. Much sweeter than grocery store lemons (Improved Meyer is technically not a true lemon, but actually a cross between a lemon and a mandarin orange). Plants can reach 8 feet tall at