Shape ash trees early on or face pruning pickle
Question: We have two 15-year-old Fan Tex Ash trees that are spreading out too far. How far can we cut them back without killing them?
Ash has little ability to come back from cut limbs if you cut back too far and into larger wood. Begin to structure the tree fairly early and stay on top of it, but if you let it go too long and then cut it back, you may have problems.
Cut it back to side branches that are growing in a desirable direction, but you cannot prune it back by what we call heading cuts (stubbing it back) and hoping these will re-sprout. You can cut back into 2- or maybe 3 -year-old wood (there are still side buds remaining that can grow), but if you cut into a limb with no buds, it will probably die back. If a limb is a problem, remove the entire limb back to its source.
I will put on my blog a photo of a thinning cut made by removing a larger limb.
Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at xtremehorticulture.blogspot.com.