I Have A Mess I Inherited A Small Pistachio Orchard Which Is Proably 5 Years Old It Appears Rootstock Wasn’t Ever Trimmed Now I

Question

have trees with red leaves and grafted green leaves. When can I prune back rootstock and can it be done all at once or gradually

Answer 1

Suckers growing from the rootstalk should be removed as soon as they are noticed. Allowing them to grow can divert energy from the desired upper branches as well as take over the tree. Go ahead and remove them all now.

https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-sucker-removal-and-tree-sucker-control.htm