Growing Turfgrass in Shade
Growing turfgrass in the shade is a major problem for many homeowners because an estimated 20 to 25 percent of all grassy areas in the U.S. are shaded to varying degrees.
While it's not always advisable to even try to maintain beautiful turfgrass in all shaded conditions, the following steps are recommended to maximize turfgrass in shady areas.
Even the most shade tolerant turfgrass needs at least 50 percent sunlight or a minimum of four hours of sunlight daily to survive.
Pruning a tree's canopy and its lower 8 to 10 feet (92.5 – 3 m) of limbs will allow more sunlight to reach the ground, but it may be destructive to the tree or spoil its natural appearance. If you can't achieve minimal sunlight for turfgrass, switch to a more shade tolerant ground cover.
Select the most shade tolerant turfgrass species possible for your climate. Not all turfgrass species are created equal, especially when it comes to light requirements. Various independent researchers have concluded the following rankings for shade tolerance.
For warm season turfgrass, recommendations are (starting with the most tolerant) – St. Augustinegrass; Centipedegrass; Zoysiagrass; Bahiagrass; Carpetgrass; Bermudagrass.
For cool-season turfgrass (most shade tolerant first) – Fine fescue; Bentgrass; Rough bluegrass; shade tolerant cultivars of Kentucky bluegrass; Tall fescue; Perennial ryegrass; and non-shade tolerant cultivars of Kentucky bluegrass.
(Consult with a Master Gardener, top-quality garden center or professional turfgrass sod producer in your area for their specific cultivar recommendations. That also should include considerations for maximum and minimum temperatures and disease factors.)
Select trees that compliment turf's presence.
Trees with dense canopies and/or shallow root systems create problems for turf. Avoid maples, oaks, magnolias, elms and sweet gums because of their dense canopies. Steer away from beeches, maples and willows because of their shallow root systems.
The open canopies of trees such as poplars, birches, pines, locusts and ginkgos can work well in concert with turfgrass.
Adjust turf maintenance practices to maximize the chances of success.
Water infrequently, early in the morning, applying enough water at a single time to moisten the soil five to eight inches (12.5 to 20 cm) deep. This approach will reduce the potential outbreak of turf diseases that thrive in damp, shady areas.
Mow at the maximum height range recommended for the specific turfgrass cultivar, using a sharp mower blade, and removing no more than the top one-third of the turfgrass blades. Most heavily shaded turfgrass grows more upright and stringy to increase the leaf surface and capture any available sunlight. Mowing at a greater than normal height allows this phenomenon to continue.
Fertilize at half-rates of nitrogen, as compared to the sunnier areas of the lawn, and increase potassium rates. Nitrogen encourages succulence that can decrease wear tolerance and increase disease susceptibility. Potassium can improve wear tolerance and decrease disease susceptibility.
Herbicide applications should be used rarely because this will place yet another stress on an already less than ideal growing situation.
Reduce heavy use of the shaded turfgrass areas. As fragile as shaded turfgrass plants are, it does not take much to tear out their shallow root systems, or otherwise damage the plant beyond its ability to recover. Limiting heavy use of these areas will give the turfgrass more opportunities to battle the other shortcomings it is contending with already.
Another suggestion, which may not be practical in all situations, is to simply plan to re-sod heavily shaded areas every few years, as part of the yard's overall maintenance and improvement plan. Stripping off the nearly non-existent turfgrass and replacing it with dense, mature turfgrass sod, can immediately refresh a shady area.
Accepting the fact that even the most shade tolerant turfgrass will thin-out over two to five years and planning to re-sod at that point can accomplish a homeowner's dream.