I was 5 years old when Steven Spielberg’s “Close Encounters of the Third Kind” was released, and although I don’t remember what age I was when I first saw the film, I do remember I was captivated and scared! Those intruders from outer space really grabbed my attention. This doesn’t relate to golf course maintenance at all, but the title is catchy and when it comes to tree roots intruding into greens, the results can be scary!
As we get rolling in 2024, I have already seen several courses with notable damage on greens thanks to trees nearby. When considering trees close to greens, the typical focus is on shade and air circulation. These are real problems, but sometimes the intruding roots pose a bigger threat to turf health. A common perception is that tree roots extend only to the outer edge of the drip line. But tree roots extend much farther, sometimes as much as two or three times the height of the tree! In the Desert Southwest, palm trees are popular. While they don’t cast much shade, their intruding roots are prolific and persistent. Palm trees are often 50 feet tall or more and their roots will extend potentially hundreds of feet. The turf environment is much more attractive for tree roots than the native desert, so roots often extend much farther into the turf than desert soils.
So, what distance should trees be kept from putting greens? As far as possible! At minimum, trees should be 20-25 yards from the green perimeter. Another question I get asked is whether root pruning is successful. Root pruning is recommended, but the benefits are temporary. Root pruning should be done near the edge of the drip line to a depth of about 12 inches. Troublesome areas should be pruned every year or every other year.
Spring is rapidly approaching and there is no time like the present to keep those intruders out of your putting greens. Remove trees close to greens or root prune to limit feeder roots that are invading the rootzone. For more information on tree management, reach out to your regional USGA agronomist.
West Region Agronomists:
Brian Whitlark, regional director – bwhitlark@usga.org
Cory Isom, senior consulting agronomist – cisom@usga.org