Ask an Arborist: What can I do to get my trees and lawn to co-exist?
Q: Is it possible to have a healthy lawn under my trees?
A: Trees and turf do not naturally coexist. However, getting recommendations from an arborist and a turf care expert can give your trees and turf the absolute best chance to be as healthy and aesthetically pleasing as possible.
It isn’t always as straightforward as a homeowner may believe or hope it to be.
Take this situation into consideration: Homeowner Bob wants to replace an area of their lawn where Bermuda grass is no longer thriving due to too much shade. Bob sees other lawns in the neighborhood with St. Augustine grass that is thriving with some amount of perceived shade, and decides to have the guys that mow his grass install new St. Augustine sod beneath the canopies of three Red Oak trees that cover about half of the front yard.
Prior to install, the yard guys then use a tiller to prep the soil and incorporate compost so that the sod will do really well and get established very quickly. They install the new St. Augustine sod and Bob waters twice a day every day for two weeks. He then backs that down to just once a day, and finally down to watering every other day. Six months later, all of the sod is nearly dead and the trees are nearly dead as well.
The problem was that the yard guys installed Floratam St. Augustine which doesn’t tolerate shade. There are multiple varieties of St. Augustine grass for different situations, which you and your lawn guys may not be aware of.
They also tilled the top four inches of soil to prep for the sod, not realizing that the bulk of the fibrous/feeder roots of the Red Oaks are in the top 4-6 inches of soil. After cutting and tearing approximately 75% of the fibrous roots of the Red Oaks, Bob commences to apply more water than the Red Oaks have ever experienced in their lifetime. Now the stressed Red Oaks are susceptible to fungal pathogens entering their vascular system through thousands of open wounds from the tilling. Fungal pathogens then “clog the arteries” of the Red Oaks and they begin to decline.
This error could have been avoided by consulting with an arborist and a turf care expert prior to the installation of new sod, and with a few adjustments - or a recommendation to change to a shade-tolerant plant choice, this project could have been accomplished successfully.
- Kenneth Smith, ISA Certified Arborist