While shade trees are an important and prominent feature in many landscapes, they can be very competitive with turf, causing problems that can lead to the turf’s decline. Trees compete with grasses for light, water and nutrients. Additionally, air flow under trees is usually restricted, increasing humidity and disease pressure. In response, the turfgrass stand density decreases as turfgrass plants become more succulent with elongated leaves and restricted roots. These factors make it a challenge to maintain dense, healthy turf in the shade.

Turf performs best with a minimum of four to six hours of full sun per day. Before struggling to maintain turfgrass underneath trees, evaluate the need for turf in that area. A better choice may be to use shade-tolerant ground covers, rock beds, mulch or pavers instead of turfgrass. If the shaded area is not trafficked, a ground cover or ornamental bed may be easier to maintain and be more attractive. If there will be heavy traffic in the area, consider stone pavers, rock pads or mulch.

Though all turfgrasses perform better in full sun than in the shade, some grass species perform adequately in shade. Consider using the following mixes for planting in the shade: 100 percent tall fescue; 50 percent fine fescue with 50 percent Kentucky bluegrass; or a combination of 50 percent fine fescue, 30 percent Kentucky bluegrass and 20 percent perennial ryegrass.

Follow these steps to improve turfgrass grown in the shade.

Step 1

Selectively prune and thin tree limbs to allow better penetration of sunlight and increase air circulation. This should be done every year or every other year as limbs regrow.

Step 2

Mow shaded turfgrasses at a minimum of 2.5 inches, but preferably 3 to 3.5 inches to leave the maximum leaf area for photosynthesis.

Step 3

Irrigate only as needed to prevent turf from becoming drought stressed. Deep and infrequent irrigation is preferred over shallow, frequent irrigation.

Step 4

Grass plants in shade are slow growing and succulent, therefore needing less nitrogen than grass plants growing in full sun. In most cases, apply 1 pound of nitrogen per 1,000 square feet of turf in September and in November to provide adequate fertility for the entire year. Additionally, shade-loving broadleaf weeds, such as wild violet or ground ivy, and diseases (powdery mildew and dollar spot) thrive in shaded areas. Some control products have restrictions on use in the shade, so be sure to follow the label for most the effective use.

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Source: Purdue University Extension, Department of Agronomy