isaiah, I assume these are Chinese variety? Yes 9 foot is much too close. The areas of the trees that are most productive are those exposed to direct sunlight. I suspect only the very tops will have much fruit; therefore you probably would be better off with fewer but larger trees.

no. buy a third one. they can not be transplanted either.

Yes, they can be trained as one tree by limiting the number of scaffold branches.

Thank you all. Harvestman, here's my situation. I have 4 plant going across..A, B , C, D. A is a trainable mango. B, is a chestnut, C is a passion fruit, that can have 9' on each side, and D, is a chestnut.

Harvestman, do I have to pull out the chestnut?

Wow, are you growing chestnuts near the beach in CA or Fl?

A chestnut tree, even if it has two trunks and is technically two trees, still requires a great deal of space. I was assuming you had lots of room and the trees were merely planted too close but had enough space for a mature tree. Then they could function very well as a self fertile "single tree".

If you have land where you can move the chestnuts and they haven't been in the ground long you can move them when dormant. They are hard to transplant once they've sent down a striker root, but very young trees can be transplanted successfully.

Thanks, they ate still about 2.5 feet high. Will pull out. Thanks.