TM 5-803-13/AFM 126-8
period, the grasses turn brown. Overseeding with cool-
grama (Bouteloua gracilis) and buffalograss (Buchbe
season grasses will provide winter color and protection
dactyloides) are appropriate grasses for silt and clay
for year-round use. Most warm-season grasses are
loams in unimproved areas (75-25). In sands and sandy
propagated by vegetative methods such as sprigging or
loams, the percentage of buffalograss should be replaced
stolonizing rather than by seeding. Major species of
with sand dropseed (Sporobolus cryptandrus).
(2) Nurse grasses. Frequently, a mixture will con-
warm-season grasses are Bahiagrass, centipedegrass,
Bermuda grass, St. Augustine and zoysia.
tain a percentage of nurse grass. Nurse grasses are fast-
(2) Cool-season grasses. These grasses grow
germinating, temporary grasses which emerge prior to
most vigorously during the spring and fall when tempera-
other grass species. They favorably alter the microclimate
tures are cool and experience a dormancy period during
conditions of the site for other species and provide
hot summer months. They retain their color throughout
erosion control where applied mulches are impractical.
the winter and are usually propagated by seed, rather than
Because of their competitive nature, nurse grasses should
vegetatively. Major cool-season grasses are bentgrass,
comprise less than 20 percent of the total mixture and
Canada bluegrass, Kentucky bluegrass, chewings and red
should not be used in areas of low rainfall. Annual
fescue, tall fescue and perennial ryegrass.
ryegrass (Lolium multifiorum) and redtop (Agrostic alba)
(3) Transition zone grasses. Because the
are appropriate for use as nurse grasses.
(3) Winter overseeding. The practice of seeding
transition zone is an area of overlap between warm and
cool season grasses, the boundary shown in figure 4-1
cool- season grasses into an established stand of grass
should be used only as a guideline. Warm-season grasses,
during the fall is known as winter overseeding. This prac-
in order to be adaptive in this area, must display tolerance
tice is common in warmer regions of the country where
to cool conditions. Cool-season grasses, on the other
Bermudagrass and other grasses become dormant in the
hand, must be tolerant to heat and drought. In most cases,
winter. The practice of overseeding is not compatible
a given species as a whole will not display these qualities,
with all dormant winter grasses, especially the dense-
though individual cultivars may. Bentgrass, Bermuda
growing types such as St. Augustine, zoysia and
grass, Kentucky bluegrass, tall fescue and zoysia may be
centipedegrass. Winter overseeding provides the winter
successfully grown in the transition zone.
color, uniformity and active root growth required for
b. Seed mixtures and blends. A more satisfactory
year-round use. When warm temperature resume in the
stand of turf can often be provided by selecting a blend or
spring, the cool-season species die hack and the warm-
mixture of species or cultivars than by use of any single
season species again dominate.
(a) Improved or semi-improved areas. A
variety. Selection of compatible turfgrass is based on
similar texture, color and maintenance requirements. It is
single species or a mixture of species may be used for
advisable to include grasses in the seed mixture which
over- seeding to provide the desired qualities.
will increase disease tolerance, adapt well to moisture or
Appropriate single species are rough bluegrass (Poa
temperature extremes, increase the range of tolerance to
trivialis), red fescue (Festuca rubra) and annual ryegrass
sun and shade, and improve the rate of establishment.
(Lolium multifiorum). Appropriate mixtures are tall
Propagation of mixed grasses should be by seed only. For
fescue (Festuca arundinacea), red fescue and perennial
this reason, mixtures of warm-season grasses, most of
ryegrass (Lolium perenne); bentgrass (Agrostis spp.),
which must be propagated vegetatively, are generally not
rough bluegrass and red fescue; Kentucky bluegrass (Poa
considered practical. Usually only one or two grasses can
pratensis), rough bluegrass and red fescue; and Kentucky
be expected to persist longer than 5 years in a mixed turf.
bluegrass, tall fescue and perennial ryegrass.
(b) Unimproved areas. Either burclover
Grasses which do not contribute to a long-lasting turf
should not be included in the blend except for use as
(Medicago hispida) or crimson clover (Trifolium incar-
nurse grass to provide quick cover for erosion control.
natum) may be used for overseeding in unimproved areas.
(1) Common seed mixtures. One of the most com-
(c) Alternatives to turf. In areas with poor site
monly used mixtures is Kentucky bluegrass (Poa
conditions, it is advisable to consider treatments other
pratensis) and chewings fescue (Festuca rubra). They are
than turfgrass. The use of turfgrass alternatives generally
usually represented in equal proportions (50-50) except
reduce maintenance requirements.
(4) Miscellaneous grasses. Miscellaneous grasses
in areas with sandy, droughty soils or in deep shade. In
these areas a higher percentage of chewings fescue is
which do not qualify as turfgrasses may be appropriately
included (30-70). In the Pacific Northwest, an
used in some situations. These grasses are often more
appropriate mixture for recreational areas is equal
tolerant to harsh conditions and can be more easily
proportions (50-50) of Kentucky bluegrass and perennial
established, especially in areas of the arid West. Further
ryegrass (Lolium perenne). In areas of the arid West,
information on local adaptation should be obtained from
mixtures of native grasses are most appropriate. Blue
county Agricultural Extension Service agents, university
4-3
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