Root Graft Species

Hello Mirai community, I’m planning my first ever root grafts. I’m growing several red maple seedlings and plan to graft them onto a Japanese maple and a Trident but I am wondering if there are any problems to be aware of when mixing different subspecies and varieties as grafts? I also want to do root grafts on a Blue oak. Wondering if I can successfully use Valley oak for the grafts? Can an evergreen oak be grafted onto a deciduous oak and vice a versa? How old should the saplings be before being grafted? A year? Two or three?

My guess is that grafts between species within a genus (Acer or Quercus) will be fairly successful. It is fairly common to graft fruit trees this way and bonsai species like pines and cedars. The biggest issue is that you may end up with some roots that look different from the others - texture and/or color.

I like to do root grafts with whips that are about 1/8 - 1/4 inch (3 - 6 mm) in diameter. The smaller ones are easier to bend for an approach graft while the larger ones are better for thread grafting since the buds at the small end of the whip will more easily fit through the larger hole needed for the bottom of the whip. My experience is that the groove for an approach graft should be at least as deep as the diameter of the graft stock to insure it does not heal and push the graft out of the groove.

I hope this helps and good luck. - Marty


Thanks Marty. Excellent and useful information. I’ll plan to push on with my root grafting experiment.