We have a four year old key lime that has never produced fruit or flowered. The tree is in full sun, next to both lemon and orange trees that produce every year. The soil has more clay in it than would be preferred, but the other two trees are doing well. It is on a drip system and the soil never gets boggy. If anything it is on the drier side of things. The tree looks very healthy with rich green leaves and many sharp spines. It has never suffered from any leaf drop or yellowing. We are about ready to dig it out, but wondered if you might have any suggestions for a non-bearing tree. Thank you for any help you can provide!