Managing Turf in Shade

1
Managing Turf in Shade

• Dr. John Stier
• University of Wisconsin

2
Adaptation of Turfgrasses

• Evolved in Eurasia
• Grazing pressure
• Outer edges of forests

3
The Shade Environment

• Reduced light
• Low air movement
• High humidity
• Long periods of leaf wetness
• Moderated temperatures

4
Why Turf Dies in Shade

• Lack of light
• Diseases
• Tree root competition
• Traffic exacerbates problem

5
Reduced Light

• Quantity
• Full sun 2,000 micromoles m-2 sec-1
• 50 mol per day
• 50 shade physiological problems
• 70 shade noticeable decline
• 10-20 shade growing limit
• Quality
• Less blue, more red
• Etiolation occurs

6
Photosynthesis Respiration

• Photosynthesis
• Sunlight CO2 Chemical energy O2
• During sunny periods
• Respiration
• Chemical energy ? CO2 H2O
• 24 hrs/day, 7 days/wk
• Compensation point
• Photosynthesis Respiration

7
Morning vs Afternoon Sun

• Morning sun best
• 4-6 hrs minimum
• Afternoon
• Higher temperatures photorespiration

8
Turf Responds to Low Light

• Fewer leaves
• Longer, narrower leaves
• Thinner cuticle, thinner leaves
• Less roots, less rooting depth
• Vascular system breaks down

9
Diseases

• Microdochium patch
• (pink snow mold)
• Powdery mildew

Microdochium mycelium on Kentucky bluegrass at
10 light
10
Powdery mildew on Supina
bluegrass Kentucky bluegrass resista
nce to powdery mildew
11
Managing Turf in Shade

• Mowing
• Increase height 3-4 inches
• Fertilization
• Maintain frequency (3-4 times/yr)
• Cut rate in half (0.5 lb N/1000 ft2)
• 30-50 slow-release N
• Irrigation
• Deep, infrequent
• Early in day

12
Managing Turf in Shade

• Prune trees, remove shrubs
• Minimum branch height 10 ft
• Avoid tree bark injury
• Maintain aesthetics
• Recommend certified arborist
• Tree root pruning not usually advisable
• Plant low density trees
• Lindens, birches
• Avoid oaks, maples

13
Selective Pruning
After
Before
14
Turf Species for Shade

• Relative shade tolerances
• Supina bluegrassgtrough bluegrass, fine fescue,
  tall fescuegtbentgrassgtperennial ryegrassgtKentucky
  bluegrass
• Moist shade Supina or rough bluegrass
• 10 or more in mixture
• Dry shade Fine fescue or tall fescue
• Chewings, creeping red, hard fine fescues
• Do not mix with other types

15
Mow High
Shaded Turf Management
Use half-rates when fertilizing
Deep, infrequent irrigation Prune
trees/shrubs judiciously
Plant better species
16
Shade Management

• Keep traffic off turf
• Remember compensation point!
• Build walkway
• Use fencing
• Broadleaf or non-living groundcovers
• Ivy, Lilies of the Valley, etc.
• Stone, bark mulch

Walkway protects shaded turf