02 Nov Growing Grass in Shaded Areas
Growing Grass in Shaded Areas
Growing grass in shady conditions is a common challenge for many homeowners. It is common knowledge that grass cannot be grown in total shade (like all plants, grass requires sunlight to photosynthesize), but the questions “how much shade is too much?” or “what is the least amount of sunlight required to grow a healthy lawn?” are asked very frequently.
The short and simple answer to this question is that in order to survive, a lawn using certain shade tolerant varieties will need at least four hours of direct sunlight, preferably from 10 am to 2 pm. To thrive, a lawn needs even more sunlight. For lawns that receive less than four hours of direct sunlight, an alternative groundcover should be considered.
Managing Shady Landscapes
The three major factors to consider when managing shady landscapes are 1) the kind of shade challenge the lawn is facing, 2) the shade tolerant grass options available in the region, and 3) fungal disease in shady landscapes.
Different Kinds of Shade & Changing Shade
Not all shade is equal, and not all shade is permanent. Filtered sunlight (partial shade) from a tree is preferable to zero sunlight (complete shade) from a building or other large, permanent structure. Trees may be thinned or removed while buildings cannot be altered to accommodate the needs of a lawn. It is important to consider that as a landscape matures and trees grow larger canopies, previously healthy lawns may decline with diminished sunlight. After taking the steps of understanding and managing (if possible) the source of shade, the next factor to consider is the shade tolerant grass options available in your specific region.
Comparative Shade Tolerance of Different Grass Species and Cultivars
Listed below are eleven grass species listed from most to least shade tolerant.
- Fescue, Red
- Tall Fescue
- St Augustinegrass
- Seashore Paspalum
- Kentucky Bluegrass
- Perennial Ryegrass
- Bermudagrass, Common
The shade tolerant grass species available for use will depend on where you live. In the cool season areas, fescues are the most shade tolerant. In warm season areas, St. Augustinegrass is the most shade tolerant, followed by zoysiagrass. To learn more about cold and warm season grasses and the difference between the two, view THIS POST.
Comparative Shade Tolerance of Different Cultivars
A cultivar is a specific kind of grass within a species. For example, Floratam and Palmetto® are both St. Augustinegrasses, but different cultivars. While both are shade tolerant, Palmetto has shown to be one of the most shade tolerant cultivars among all St. Augustinegrass.
Within zoysiagrasses, a general guideline to remember is the finer the leaf blade, the more shade tolerant the cultivar. For example, EMPIRE Turf®,a medium textured zoysiagrass grown in warm season areas, has moderate shade tolerance, while both InnovationTM and GeoTM, two finer textured zoysaigrasses grown in the transition zone, have greater shade tolerance.
Whichever grass you choose, a tip for maintaining shade-tolerant varieties is to mow a bit higher than the recommended mowing height. The extra height will provide a greater surface area for the grass to photosynthesize the reduced sunlight it receives in shady conditions.
A Word About Disease
Any turfgrass grown in wet, shady environments is prone to fungal disease. Shade tolerant grasses often struggle or die from disease pressure, not necessarily from lack of sunlight. When selecting a shade tolerant grass to grow in a shady landscape, be sure to budget for several applications of systemic fungicide per year. Additionally, note that to avoid disease it is best to water less in shaded areas compared to areas that receive full sun.
A New Shade Tolerant, Disease Resistant St. Augustinegrass
In October 2018, the University of Florida released CitraBlueTM, a new St. Augustinegrass with a dark blue-green leaf blade that exhibits greater shade tolerance and disease resistance compared to Floratam. CitraBlue will be available in small quantities in Florida in late 2019 and more widely available throughout the warm season areas in the United States in 2020.