My first plum tree. Advice welcome

2016 I impulse bought a 3:1 plum with 5 grafts. Dwarf Shiro, dwarf santa rosa, Italian plum, Burbank and Dwarf Satsuma. My nursery helped me track down the grower and the grower can’t remember what rootstock they used. The trunk looks very cherry like and it was grown in PA. The grower for what it worth said it wasn’t there best work and they stopped multi grafting till they can improve there technique. I already know the Shiro is over dominate and needs to be cut down. The bag is my bad attempt to air layer off the upper section last fall. I know I was way to skittish about cutting the cambium layer, so I wouldn’t be surprised if it didn’t just heal over. I will try again after the fruit ripens. The problem I have is 1. all of the Shiro branches below the air layer (2) are turned inward. Is there any way to get a bud to develop on the lower branches? 2. Can I use the cut point of the air layer to graft a scion or two. 3. What would happen if I planted the Dwarf Shiro Air layer in the ground. Do Japanese plums grow huge? Or should I opt to turn it into some sort of Bonsai I would defiantly not be opposed to it if its workable. Oddly they labeled 3 out of 5 dwarf are there dwarf versions of each or is that just a root stock result.

  1. When you cut the top off of the Shiro it will most likely stimulate buds to form in random locations around the remaining branch especially if you also remove the undesirable buds and branches. Then just rub off any new buds that form in bad locations and leave the desirable ones to leaf out.

  2. Yes you can graft at virtually any location on a plum tree; branches, trunk or even the roots.

  3. I’m growing plums in Zone 9b so your mileage may vary but I get 6 to 10 feet of limb growth and frequently add 1" in diameter annually on Japanese plums and pluots. I prune heavily to keep them reasonably small.
    Your grower may have used Citation rootstock which is a fairly common dwarfing plum/peach hybrid. Those cultivars are not naturally dwarfs, in ideal conditions they will grow vigorously.