As you decide what grass to use for your lawn, consider how well adapted each species is to your climate and the growing conditions in your yard. Shade tolerance, or the degree to which a species of grass will grow when not exposed to full sunlight, is a critical consideration. St. Augustine grass cultivars vary in their shade tolerance, and choosing one of the most shade-tolerant varieties can help ensure that your grass grows healthily.
St. Augustine and Shade Tolerance
St. Augustine grass is generally regarded as one of the most shade-tolerant species of grass available to home owners, and grows healthily in shady areas that would be unsuitable for many other species of grass. St. Augustine is most ideally suited for well drained, fertile soils but is easily adaptable to a range of soil profiles. All these adaptive qualities taken together make St. Augustine an ideal choice for any homeowner, particularly those whose lawns have shaded areas that do not receive regular direct sunlight.
Still, some cultivars of St. Augustine grass tolerate shade better than others. The most shade tolerant varieties of St. Augustine are Bitterblue, Deltashade, Captiva, Delmar and Seville. Floratine, Classic, Jade and Raleigh varieties also do well in the shade. The cultivars least suited to the shade are Common, Palmetto, Floratam and Floralawn. Note, however, that even the least shade tolerant St. Augustine cultivars typically do better in the shade than other species of grass.
Tips for Shade Tolerance
Even the most shade tolerant varieties of St. Augustine will struggle to grow well if proper management practices are not observed. Shady areas of the lawn require less fertilizer than sun-bathed areas, so adjust fertilization rates for the entire lawn to account for this. Generally speaking, patches of St. Augustine growing in shade should not be mowed as closely as those patches growing in sunlight. Even the most shade tolerant varieties can sometimes experience problems growing if shade is excessive, particularly when excessive shade is combined with other problematic growth factors such as compacted soils, over- or underwatering, improper mowing, traffic and high or low pH.
If brown patches break out on your lawn, don't immediately assume that your St. Augustine grass is suffering from shade-related problems; the symptoms that normally indicate a lack of sunlight exposure mirror those of many other common lawn problems, including over- or underwatering, over- or underfertilization, drought stress, fungal or bacterial disease, insect pest damage and improper use of herbicides, fungicides or insecticides. If you suspect the symptoms are not due to shade intolerance, local university extension offices can often provide a remote diagnosis upon sending them a sample of the affected grass.