Introduction
Natural history of grasses
1. Frequently defoliated by fire, grazing,
lawn mowers
2. Protected from lasting damage by intercalary
meristems
3. Fibrous, short-lived root systems bind
the soil, prevent erosion
4. Spikelet is the basic unit of the inflorescence
for the 10,000 species of grasses in the world
5. Wind-pollinated, flowers not showy
Cultural heritage’s are at the
root of some turfgrass perceptions
1. Mediterranean cultures (e.g., Alhambra)
make little or no use of turfgrass
2. Turfgrass originated in northern Europe
and East Asia
3. Florida landscape architects and landscape
managers are still discovering the potential and limitations
of our climate
Why grow turfgrass? There
are many specific examples which fit into these four categories;
(How do these relate to the components of turfgrass quality,
uniformity, texture, density, color, and growth habit?)
1. Recreation
2. Safety and sanitation
3. Esthetics
4. Conservation
Considering our uniquely fragile Florida
ecosystems:
1. Turfgrass can be viewed as environmental
resource
2. To be managed as a part of the whole
3. In order to reduce impacts and increase
maintenance efficiency
Grasses
St. Augustinegrass
Native to Old World tropics, e.g. Africa
1. Competitive against weeds
2. Adapted to wide range of Florida conditions
3. Recovers poorly from drought
4. Shade tolerant cultivars exist (e.g.,
Seville, Delmar, Jade, and possibly Palmetto)
5. Susceptible to chinch bugs (except FX-10)
Bahiagrass
Native to subtropical South America
1. Very drought resistant
2. Poor tolerance to shade and salt
3. Poor response to winter irrigation,
heavy fertilization, and some herbicides
4. Susceptible to mole crickets, weed invasion
5. Argentine cultivar is superior to Pensacola
Zoysiagrasses
Native to East Asia, e.g., Japan
1. Slow growing, difficult to establish
2. Highly rhizomatous, hard to eradicate
3. Performs poorly in deep sands due to
sting nematode problems?
4. Very attractive when properly mowed
5. El Toro cultivar has performed well
Centipedegrass
Native to China
1. Slow growing, not very competitive
2. Adapted to heavy soils; performs poorly
in deep sands due to sting nematodes?
3. Low growing, often attractive
4. Moderately shade tolerant
Bermudagrasses
Native to Old World, e.g., Africa
1. Rapid growth; very responsive to fertilization
2. Recovers well from traffic
3. Requires frequent mowing and pest control
4. Poor tolerance to shade
Miscellaneous turfgrasses for the West
Indies, including Florida
(Mostly natives of the region)
1. Carpetgrass (2 species of Axonopus)
2. Seaside paspalum (P. vaginatum)
3. Hurricanegrass=Seymourgrass (Bothriochloa
sp.)
4. Buffalograss (Buchloe dactyloides)
Cool season turfgrasses
(How do C3 and C4 grasses differ in
shade tolerance, maximum photosynthetic rate, water use,
and insect resistance?)
1. Kentucky bluegrass (Poa pratensis)
2. Tall fescue (Festuca arundinacea)
3. Creeping bentgrass (Agrostis palustris)
4. Perennial ryegrass (Lolium perenne)
5. Red fescue (Festuca rubra)
Water and irrigation
Four factors in turfgrass evapotranspiration
(water use)
Evapotranspiration is an energy transfer;
the same kilocalories are needed to evaporate a gram of
water from a leaf as from a pond
1. Radiant energy (less evapotranspiration
in the shade)
2. Wind speed (less evapotranspiration
from tight canopies)
3. Relative humidity (technically, "vapor
pressure deficit," the dryness of the air)
4. Temperature
5. Because evapotranspiration is an essentially
passive physical process, different species of turfgrass
and different vegetation types (e.g., forests vs. grasslands)
all use about the same amount of water under the same four
physical conditions of radiant energy, wind, relative humidity,
and temperature.
Determinants of turfgrass available
soil moisture reserve
1. Depth of effective root zone, i.e.,
soil moisture capacity
2. Rainfall and irrigation inputs
3. Runoff, percolation, and evapotranspiration
outputs
4. Consequently, many deeply rooted plants
use the same amount of water as shallow rooted plants, but
they can endure more days between soil saturating rainfalls
(or irrigation events)
5. It is environmentally sensitive to use
plants that are adapted to South Florida's natural wet-dry
cycles
Managing St. Augustinegrass during seasonal
drought
1. Unlike bahiagrass, St. Augustinegrass
does not recover from complete defoliation
2. Temporary (late-afternoon) wilt has
no harmful effect
3. You generally have a few days, possibly
one week, to irrigate
4. "Deep" (1 inch) watering is
probably inappropriate; we don't have sufficient soil moisture
capacity
4. Permanent (early-morning) wilt may set
in within a week of temporary wilt
5. Subsequent turf loss will be progressive;
within one week the entire turf will be destroyed
Design for sprinkler efficiency
Goal is maximum uniformity, through
head-to-head coverage
1. Proper spacing of heads
2. Sufficient pressure at the source
3. Minimal friction loss: large pipe, not
too many heads per zone
4. Water confined to the landscape (use
part-circle heads)
5. Matched heads (spray vs. rotary, etc.)
Operating an efficient sprinkler system
Goal is to sustain minimal requirements
1. Shut it off; let the grass tell you
when to water
2. Cancel automatic irrigation following
rain
3. Avoid application during times of high
wind
4. Nevertheless, inspect the pattern: catch
and measure the irrigation
5. Apply only 3/4 inch per event
Turf biota
Examples of problem organisms in South
Florida turfgrass
1. Insects: caterpillars (including sod
webworms), mole crickets, grubs (larvae of beetles), southern
chinch bug, fire ant
2. Fungal diseases: brown patch, dollarspot,
take-all root rot disease
3. Sting nematode
4. Weeds
Pest management with chemicals
1. Accurately identify the pests
2. Assess and correct any contributing
factors (e.g., over-fertilization, over-watering)
3. Spot-treat chemicals, if any, to the
affected area, according to label requirements
4. If you're not experienced, treat a small
test strip
5. Wear proper safety clothing, and protect
other organisms (people, pets, and neighboring plants)
Petrochemical controls against pests
1. Pest monitoring
2. Periodic pesticide application
3. Potential environmental harm
Genetic resistance and biocontrol approaches
1. Self-perpetuating
2. Energy conserving
3. Environmentally sensitive
Cultural practices
Fertilizer considerations
(What are the 17 elements needed for
plant growth?)
1. Excess nitrogen amplifies other costs.
2. For St. Augustinegrass lawns, 2 applications
per year is adequate (each 1 pound N / 1000 ft2).
3. Recycling clippings saves nutrients.
4. By not applying soluble nutrients from
April thru September, leaching is minimized.
5. Organic is usually not natural
6. Prices of fertilizers vary widely
Safe mowing
Can prevent 100,000s of injuries each
year
1. Protect ears, eyes, and feet
2. Clear the area (people, pets, objects)
3. Never walk backwards
4. Handle gasoline carefully
5. Mow at the right height and frequency
6. Return clippings
Turf establishment has 3 phases
1. Lag: rooting, no increase in dry matter
2. Log: exponential or compound-interest
type growth, very rapid provided sufficient water, nutrients,
sunlight, and protection from pests
3. Knit: turf roots interlock, stolons
mesh, carbohydrates accumulate, thatch begins to form
Compaction, drainage, and traffic
1. 95%+ sand can support considerable traffic
2. Wear and compaction are different phenomena
3. Vehicular turf is suitable in south
Florida
4. Other cultural practices include verticutting,
aerification, rolling, and topdressing
The integrated landscape
Shade is a challenge in growing turfgrass
1. Direct effects: inadequate photosynthesis,
just compensates for respiration
2. Indirect effects: thin turf, disease
problems (due to humidity), webworms
3. Tolerant St. Augustinegrasses are Seville,
Jade, Delmar, and possibly Palmetto
4. Intolerant are bermudagrass, bahiagrass,
Floratam and FX-10 St. Augustinegrasses
5. Can adjust tree architecture (i.e.,
selective pruning)
Close encounters of trees and turfgrass
1. Turf herbicides can kill trees
2. Mowers and trimmers injure tree bark
3. Leaf litter from trees smothers turf
4. Tree shade causes turf to thin out
5. Trees are obstacles requiring increased
costs for edging and trimming
6. Turf irrigation can lead to root rot
in trees
