This does not mean, however, that supplemental watering will not be needed for lawns during periods of drought. More research into this characteristic is currently underway. Shade Tolerance St. Augustine grasses in general are known for their shade tolerance, and Palmetto has exceptional shade tolerance, even when compared to the most shade tolerant varieties of St. Augustine. In both field shade tests under trees and laboratory testing under canopies of mesh, when several other varieties of St. Augustine grass gradually declined, Palmetto sod thickness decreased only slightly and maintained a pleasing overall appearance with consistent color among areas exposed to varying amounts of light. Most varieties of St. Augustine that have exceptional shade tolerance also have thatching problems in full sun locations.
Palmetto is less prone to thatching, and is routinely used in areas of full sun.
While many varieties of St. Augustine are not very cold tolerant, Palmetto is very cold tolerant. No other St. Augustine has proven to be more cold tolerant than Palmetto. Most warm season grasses and most varieties of St. Augustine have little or no tolerance for frost. Palmetto, however, has excellent tolerance to frost and is able to withstand several frost cycles before showing signs of winter dormancy. Frost may cause a warm season grass to go into winter dormancy, changing the color to brown or tan.