Last updated 2/26/98 |
![]() |
Improving Lawns in the Shade Zac Reicher and Clark Throssell |
AY-14 |
Shade trees are an important and prominent feature in most lawnscapes. Though trees provide cooling for us and our homes, trees are very competitive with turf, causing turfgrasses to decline in shade. Trees compete with grasses for light, water, and nutrients. Additionally, air flow under trees is usually restricted, increasing humidity and turfgrass disease pressure. In response, turfgrass stand density decreases as turfgrass plants become more succulent with elongated leaves and restricted roots. These factors make maintaining a dense, healthy turf in shade a challenge, if not an impossibility.
The choice: Trees or turf?
Turf performs best in full sun with a minimum of four to six hours of full sun per day.
Before struggling to maintain turfgrass underneath trees, evaluate the need for turfgrass
on the area. You may be better off using shade-tolerant ground covers, rock beds, or even
mulch or pavers in the shade instead of turfgrass. If the shaded area is not trafficked, a
ground cover or ornamental bed may be easier to maintain and more attractive. If there
will be heavy traffic on the area, consider stone pavers, rock pads, or even mulch.
Thoroughly consider all of the alternatives before you decide to manage turfgrass in
shade. For most shaded areas, it is more practical and more attractive to use something
other than turf. Unfortunately, shaded areas still exist where turf needs to be grown.
Following are some suggestions to improve turfgrass grown in the shade.
Pruning
Selective pruning and thinning of limbs and removal of some trees will allow better
penetration of sunlight and increase air circulation. Unfortunately, trees will naturally
regrow into voids left by pruning, necessitating pruning yearly or every other year.
Mowing
Mow cool season turfgrasses at a minimum of 2.5 inches and preferably 3.0 to 3.5 inches.
This is important for all lawns but especially for shaded lawns. Mowing at this height
leaves the maximum leaf area for photosynthesis.
Irrigation
Most shaded areas are over-watered. Irrigate only as needed to prevent turf from becoming
drought stressed. Deep and infrequent irrigation is favored over shallow, frequent
irrigation. It is better to underwater shaded turf to minimize disease pressure.
Traffic
As with all turf grown in less-than-optimum areas, minimize traffic in shaded areas.
Recuperation potential of traffic-damaged turf is severely reduced in shade.
Fertilization
Grass plants in shade are slow-growing and succulent and thus need less nitrogen than
grass plants growing in full sun. Applying 1.0 lb nitrogen/1000 ft2 in
September and in November should provide adequate fertility for the entire year in most
cases.
Pest Management
Shade-loving broadleaf weeds like wild violet or ground ivy have a tremendous vantage over
turfgrasses and usually dominate in shade. These weeds are difficult to control and even
if they are controlled, the turf is rarely vigorous enough in shade to prevent weeds from
reestablishing. This is probably the best reason not to grow turfgrasses in shade.
Crabgrass and other annual grassy weeds are rarely a problem, and thus preemergence annual
grass controls are not needed in shade. However, the perennial grassy weed nimble will
thrive in the shade and may need applications of glyphosate to control. Most herbicides
have restrictions on their use in shade, so be sure to follow the label for most effective
use. Diseases like powdery mildew and dollar spot thrive in the low-light, high-humidity
environment under trees. Moss and algae also thrive under these conditions. Selective
pruning to increase air flow should decrease pressure from these pests. Using pesticides
to control moss, algae, or turfgrass diseases in shade is recommended only on high-value
turf areas.
Overseeding
Overseeding to improve density of the turf stand is important in shady areas. Early fall
(mid-August to mid-September) is the best time to seed cool-season grasses. Be sure to
irrigate regularly to encourage germination, maintain adequate fertility, and keep falling
tree leaves off newly seeded turf to maximize sunlight to the young plants. Some turf
managers prefer to seed in early spring when no tree leaves are present. Spring-seeded
turf needs extra irrigation well into the summer to help it survive the summer stresses.
Species Selection
Though all turfgrasses perform better in full sun than in shade, some grass species
perform adequately in shade. In most of Indiana, tall fescue or fine-leaf fescue
(chewings, creeping red or hard fescues) are the species of choice for shady areas. Some
cultivars of Kentucky bluegrass and perennial ryegrass will also grow adequately in the
shade. Consider using the following mixes for planting in shade:
100% tall fescue
50% fine fescue/
50% Kentucky bluegrass
50% fine fescue/
30% Kentucky bluegrass/
20% perennial ryegrass
Table 1 lists cultivars of fine fescue, tall fescue, perennial ryegrass, and Kentucky bluegrass that have been shown to be shade tolerant.
| Table 1. Cool season turfgrass species and cultivars exhibiting shade tolerance. |
| Tall Fescue | Kentucky Bluegrass | Perennial Ryegrass |
| Falcon | A-34 (Bensun) | Birdie II |
| Finelawn | Bristol | Citation II |
| Houndog | Eclipse | Fiesta II |
| Jaguar | Glade | Manhattan II |
| Olympic | Nugget | Palmer |
| Rebel | Touchdown | Regal |
| Rebel II | Victa | . |
| . | . | . |
| Fine-leaf Fescues | . | . |
| Chewings fescues | Creeping red fescues | Hard fescues |
| Banner | Dawson | Aurora |
| Barfalla | Ensylva | Biljart (C-26) |
| Checker | Fortress | Reliant |
| Highlight | Pennlawn | Scaldis |
| Jamestown | Ruby | Waldina |
| Koket | . | . |
| Shadow | . | . |
Sources of additional information from Purdue University:
AY-9 Control of Broadleaf Weeds in Turf
AY-11 Control of Perennial Weedy Grasses in Turf
AY-20 Seeding a Turf Area in the Spring
AY-22 Fertilizing Established Lawns
HO-222 Landscape Plants for Shady Areas
Purdue University
Cooperative
Extension Service
West Lafayette
Indiana 47907
3/98
Send corrections, suggestions, and comments to danw@purdue.edu
WebWeaver Dan Weisenberger