It is an oft heard complaint, “I’m having a difficult time getting grass to grow under the trees in my yard. The soil seems to be good, but without grass any heavy rain just washes it away”.
And it is always followed by the question, “Is there any type of grass I can plant there that will grow?”
The short answer to this questions is no, there are no grasses that will grow in heavy shade this far south. Further north there is Creeping Red Fescue, but it will not grow here in the balmy latitudes of panhandle Florida.
Growing turf grass under oaks and pines means at the very least partial shade, but in most cases, there is heavy shade under large established trees. Of the five commonly encountered warm season lawn grasses grown in north Florida (Bahia, Bermuda, Centipede, St. Augusine and Zoysia), St. Augustine grass has the best shade tolerance, but it still has a requirement for some direct sunlight exposure.
Heavy shade in a home landscape can be an advantage or a detriment. When selecting turf or ornamentals, the homeowner must choose plants that grow well with the limited light. Getting turfgrasses to flourish under trees which produce heavy shade for most of the day is a near impossibility, necessitating alternate choices for ground cover.
However, there are different types or cultivars of St. Augustine. Each has a different tolerance to shade. UF/IFAS Extension turf trials have indicated the following levels of shade tolerance of St. Augustine cultivars.
Quality scores differed significantly between cultivars at different shade levels during the trial periods. Seville and Floraverde both ranked in the highest category for overall quality at 30 percent and 50 percent shade.
At 70 percent shade all cultivars had significantly reduced quality, with the lowest quality in Floratam. Floratam quality fell below acceptable levels at 52 percent shade, Palmetto at 64 percent, while Seville and Bitterblue maintained quality at acceptable levels up to 70% shade.
The turf cultivars’ best quality characteristics were reached at slightly different shade levels, ranging from 16 percent shade for Palmetto to 22 percent shade for Floratam. Quality ratings declined as shade increased beyond these levels.
Color scores also differed between grasses at all shade levels except for the 50 percent range. Seville ranked in the highest group at each light level, while Bitterblue was in the highest group at 70% shade only. All cultivars maintained acceptable color rankings through 70% shade.
This is not surprising considering the concentration of chlorophyll increases as shade levels increase. Chlorophyll is the pigment which reflects the green color in leaf blades. Its presence contributes significantly to determining how green a leaf blade appears.
As an alternative to turf grass in heavily shaded areas, consider the construction of a short retaining wall around the trees to stabilize the soil. It need not be more than eight inches high and filled with topsoil.
Transplant shade tolerant plant species to the location, but be patient as it will take time and persistence to establish the plants. Proper watering and a good layer of mulch will speed the process.
Some groundcovers to consider for heavily shaded areas include Asiatic jasmine (Trachelospermum asiaticum), Coontie (Zamia pumila), Monkey Grass (Liriope) and ferns. Spaghnum moss will flourish too.
If landscaping on the Gulf Coast under live oak trees, use Coonties and Monkey Grass. Both are salt tolerant and will handle the salt spray.
Establish a footpath to a bench and enjoy the shade beneath the trees. It will always be cooler than sitting in the sun.
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