I have a relatively large backyard, however, I had to compromise in what zones I can plant. This is the north side, I have a russell avocado (so far slow grower) in the middle a Kent mango and then an Alano sapodilla. They get very good amount of sun in the afternoon (pics in am). Can I get away with planting something in between these trees in the same row? Should I just let them be? I was thinking of star fruit or another avocado. How about two coconut palms?
Thanks for the advice!


Hey just my two cents

here goes...this is judging by assuming that the photo (second photo) is facing due North (actually looks slightly towards N.E.), and this picture was taken in the morning.
Consider these things:
You have planted your trees so that your neighbors may benefit, from, or maliciously prune improperly, or spray weird chemicals (had a neighbor round up my passion vine with 200 fruits, on the fence in full fruit. I wanted to round up his neck with my hands and squeeze for 30 seconds)
So I hope you are on good terms with your neighbors, and that they don't hate what and where you've planted for any reason.
All three trees you've selected will grow in the next 4 or so years (depending on many things of course), to form a triumvirate hedge with different growth habits and rates.
You should prune heavy on the mango, and avocado Im assuming...the slowest grower will be the sapodilla....
But geeze they are all capable of getting to be 40ft! so you are super close...but you can do it I'm sure.
As for adding fruit trees, carambola is a great candidate for shaded 50% sun, areas, with no exposure to wind...they love this, and fruit well under such environmental conditions.
Miracle fruit is same as above to an extent... great for adding to a garden with small space and limited lighting.
Also jaboticaba produces well in shade (more so than other fruit trees at least), and is amenably squeezed into tight locations and jam packed collections of fruit trees...
E. neonitida is a wonderful bush you could squeeze in, but wants fuller sun for better fruits...only gets about 8 ft tall usually, so can be kept small.
Eugenia luschnathiana
Australian finger lime!
Garcinia sp. (quite a few...pick smaller sized species)
and many others to squeeze in...but not in that row of trees, its already at maximum occupancy limit.