of Rhode Island GreenShare Factsheets
When selecting turfgrasses to establish a lawn, consider
species that will be best adapted to your environmental conditions,
intended use and the maintenance level at that particular site.
Grasses vary in tolerance of soil moisture, pH, fertility and
temperature ranges. They also vary in resistance to stresses
caused by excessive wear, mowing, insects and diseases. In
the Northeast, many species of cool-season grasses (characterized
by maximum growth in the spring and fall and semi-dormant during
hot and/or dry periods of summer) can be used alone or in mixtures
to produce a dense lawn. The principal species of cool-season
grasses for lawns are: Kentucky bluegrass, perennial ryegrass,
tall fescue and fine fescues (creeping red, Chewings and hard).
Creeping bentgrass is a cool-season grass used for very closely-mown,
high-maintenance playing surfaces such as putting greens or
croquet courts. It is not an appropriate lawn grass. Cultivars
within each species offer further options of improved aesthetic
and resistance qualities.
Certain cultivars of perennial ryegrass,
tall fescue and fine fescues also contain fungal endophytes.
A fungus living
inside these grasses enhances the qualities of the turf, but
is not visible on the grass surface. Endophytic
grasses have a high tolerance for environmental stresses
and may perform well under low-maintenance regimes. Endophytic
grasses also have resistance to leaf-feeding insects such as
sod webworms and chinch bugs. Fine
fescues containing these endophytes also resist dollar
spot, a disease associated with low fertility.
Kentucky bluegrass has fine to medium leaf texture and
is dark green in color. It spreads via rhizomes (underground
stems), allowing for good sod-forming abilities. Tolerance
is high for cold temperatures and wear, and moderate for heat
and drought. The grass becomes semi-dormant under hot and dry
conditions. It will recover quickly in cooler temperatures
and with adequate moisture. Kentucky bluegrass is best grown
in well-drained, sunny areas, although a few cultivars tolerate
some shade (e.g. 'Glade' and 'A-34'). It requires higher amounts
of N fertilizer (2-3 lb. N/1000 sq.ft. per growing season)
than some other cool-season grasses and may produce a significant
amount of thatch if over-fertilized or over-watered. Kentucky
bluegrass may be susceptible to such diseases as leaf
spot, dollar spot, stripe
smut, necrotic ring spot and
summer patch. Some newer cultivars show some disease resistance.
Perennial ryegrass has a fine to medium
leaf texture and tends to be dark green. It germinates rapidly
and is quick
to establish, making it suitable for overseeding. It is competitive
with other grasses, however, and is used either alone or in
combinations with Kentucky bluegrass or fine fescues. Use no
more than 20% perennial ryegrass when mixing with other grass
species. It is wear- and heat-tolerant, but will not withstand
shade and drought well. It is susceptible to ice cover injury,
although some cultivars recover from this damage better than
others. Perennial ryegrass does best on well-drained soils
with moderate fertility. The nitrogen requirement for perennial
ryegrass is approximately 2 - 3 lb. N/ 1000 sq. ft. per season
with little thatch accumulation. Perennial ryegrass is most
susceptible to diseases such as brown
patch, Pythium blight, dollar
spot, red thread and rust.
Several cultivars of perennial ryegrass contain beneficial
fungal endophytes, which provide some insect resistance.
Many new, finer textured, darker
green "turf-type" varieties
now make tall fescue an option for lawns. Tall fescue is slow
to establish, preferring temperatures above 70 degrees F for
optimal germination. It has only a fair recovery potential,
but it is both heat and drought tolerant. Tall fescue performs
best in well-drained soils in open, sunny areas but can withstand
moderate shade. Overall, it is more shade tolerant than Kentucky
bluegrass and perennial ryegrass, but less so than the fine
fescues. Tall fescues require 2.5-3 lb. N/1000 sq. ft per growing
sea-son with minimal accumulation of thatch. Most cultivars
should not be mown at less than 2 inches. Tall fescue is highly
susceptible to brown patch, red
thread and Pythium blight.
Creeping Red Fescue
These narrow-leaved, medium-green to dark green grasses
can be used either alone or in combination with other grasses.
Each species varies somewhat in terms of growth characteristics,
but all are ideal for low-maintenance situations. They are
very tolerant of low pH and fertility, and of drought and shade.
Fine fescues do not perform well under hot, humid conditions
or with high levels of fertility. Fine fescues become semi-dormant
in heat and drought, but recover quickly. These grasses require
1-2 lb. N/ 1000 sq. ft. per growing season with minimal production
of thatch. Fine fescues are susceptible to leaf
spot, red thread and dollar
spot. Endophytes containing cultivars have dollar spot
and some insect resistance.
A grass seed mix is made up of two or more different
species of grasses. A typical home lawn seed mix, for example,
may be made up of varieties of Kentucky bluegrass, perennial
ryegrass and fine fescues. A mix of these species is generally
fairly adaptable to differing site conditions (shade, full
sun, dry, moist). Most lawns should be made up of a mixture
of grasses appropriate for the particular site. A blend is
made up of two or more cultivars or varieties of the same species
of grass. For instance, a blend of perennial ryegrass might
be made up of three or more varieties of perennial ryegrass.
Blends are often used in highly-maintained lawns where extremely
uniform appearance and performance are required, or for overseeding
established lawns or play areas. For either blends or mixes,
include at least three cultivars or varieties.
Several other cool-season grasses can be used for special
situations. These include:
Rough bluegrass, Poa trivialis:
This light green grass is shade-tolerant. It requires moist, fertile soils,
with some shade preferred. It is an aggressive grass but will not tolerate
heat, drought or traffic. Rough bluegrass requires approxi-mately 2 to
3 lb. N/1000 sq. ft. per season. Because it spreads by stolons (aboveground
stems), it does not mix well with other species. Cultivar choices are limited.
Alkaligrass is suited for high pH or salty soils. This dark-green, medium to
fine-textured, cool-season grass is good for use along road-sides and in
areas near the coast which are subjected to annual salt spray. Alkaligrass
tolerates regular mowing, but also maintains an excellent aesthetic value
in unmown situations. A few cultivars are available of this species.
Supina bluegrass, Poa supina:
This is a relatively high-maintenance, aggressive and vigorously growing grass.
It is typically light green and spreads via aboveground stems (stolons).
Supina bluegrass is being used and evaluated under very high-traffic situations
such as athletic fields. Very limited cultivars are available.
Bentgrasses, including creeping bentgrass, are typically
grown under low-mown (less than 1/2 inch), high-maintenance situations.
They are the grasses of choice for putting greens, bowling greens
and croquet courts. They become a weed in a higher-mown lawn
situation, forming "puffy" circles of grass. Bentgrasses are
prone to scalping.
Kentucky Bluegrass: 'Georgetown' (developed at
URI), 'Award,' 'Midnight,' 'Blackstone,' 'Glade'
Perennial Ryegrass: 'Palmer III,' 'Calypso II,'
'Secretariat,' 'Panther,' 'Brightstar'
Creeping Red Fescue: 'Florentine,' 'Shademaster
Chewings Fescue (These cultivars do well in
mixes with Kentucky Bluegrass): 'Jamestown II' (developed
at URI), 'Brittany,' 'Tiffany'
Hard Fescue: 'Reliant II,' 'Defiant'
Adapted from the University
of Massachusetts Extension, 1999
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program