OK. I admit it. I have given up. I came to the conclusion last fall that grass just would not grow in the corner of my lawn near the ornamental cherry trees. The shade there is so dense that my fescue, no matter how lush in April, thinned out to bare soil for five years running. This spring I planted white impatiens, golden hosta and variegated ivy there and the spot looks better than it ever has.
Trees and shade look nice in the landscape. However, it is difficult to grow grass under trees because not only the quantity but also the quality of the light changes in the shade. In full sun, light is in the “near red” range of wavelengths. In the shade it shifts to the “far red,” which is less effective for photosynthesis. The result is a reduction in the food needed for turf growth. Leaves and stems of grass plants are thinner in shade. Moisture from dew under trees takes longer to evaporate. The additional moisture may contribute to an increase in disease.
With the deck stacked against it, it is remarkable that any grass grows under trees. If you let experience, rather than me, be your teacher, these tips will help you grow grass in the shade.
CHOOSE RIGHT GRASS Under high pine tree shade, bermudagrass and zoysiagrass can grow successfully. Beneath the shade of a dogwood or an oak, both fail miserably. Fescue is the most shade-tolerant grass that is adapted to the Atlanta area but there is little difference between the various named fescue seed brands.
PRUNE TREES Selective pruning and thinning of limbs within the tree canopy will allow better sunlight penetration. Single tall trees should have all limbs removed below 10 feet. Rake and remove leaves or needles before they accumulate.
MOW HIGHER Grass in the shade should be cut approximately 1/2 to 1 inch higher than the grass growing in full sunlight. This will allow more leaf area to intercept the limited amount of sunlight. Avoid scalping turf in the spring. Decline of turf in shade often begins after a single episode of scalping.
WATER MORE Tree roots compete with the turfgrass for available soil moisture. In addition, the distribution of moisture from rainfall is poor under a tree canopy. The tree leaves block or deflect the rainfall. This yields an uneven soil moisture pattern. As a rule of thumb, turfgrass in shade needs 1 inch or more of water per week. In the absence of rainfall, wet the soil to a 6-inch depth. This may take 2 to 3 hours for one irrigation application.
MINIMIZE TRAFFIC During the summer months, minimize the traffic and activities in the shaded grass areas. This will reduce the wear stress on the turf. If the grass is in a path where traffic can not be avoided, place stepping stones or pine bark to mark the trail.
LIMIT FERTILIZER Grass grown in the shade should receive half the fertilizer than that in the sun. Feed lightly in the early spring before tree leaves come out. Fertilize little or none throughout the summer.
LIMIT WEEDKILLERS Use broadleaf weed controls sparingly on shaded lawns. The best approach for general weed control would be an application in the mid-fall to late-fall period. Spot-spray special weeds like wild violet. Crabgrass controls are not necessary in a shade environment since crabgrass needs a high light intensity to germinate.
USE GROUNDCOVER OR MULCH In areas where even fescue fails, think about using light-colored groundcovers like I did. A layer of pinestraw or pine chips looks much better than bare dirt. As one of my gardener buddies says, _ج
