St. Augustinegrass for Florida lawns


St. Augustinegrass (Stenotaphrum secundatum
[Walt.] Kuntze.), is widely adapted to the warm,
humid (subtropical) regions of the world. It is
believed to be native to the coastal regions of both the
Gulf of Mexico and the Mediterranean. In Florida, St.
Augustinegrass is the most commonly planted
turfgrass in the urban, coastal areas. It performs best
in well-drained, fertile soils but can grow
satisfactorily in a wide variety of soils. To produce
an acceptable quality lawn, St. Augustinegrass
requires irrigation and moderate fertility.
 

Advantages

St. Augustinegrass produces a green to
blue-green dense turf that is well adapted to most
soils and climatic regions in Florida. It has relatively
good salt tolerance and certain cultivars possess good
shade tolerance. Establishment of St. Augustinegrass
from sod is quick and easy. Several different
cultivars of St. Augustinegrass sod and plugs are
available from garden centers and custom sod
installers throughout Florida.

Disadvantages

St. Augustinegrass, like most turfgrasses, has
certain cultural and pest problems. It does not remain
green during drought conditions without
supplemental irrigation. It produces excessive thatch
under moderate to high fertility and frequent
irrigation. It has poor wear tolerance and some
varieties are susceptible to cold damage. The coarse
leaf texture is objectionable to some people. The
major insect pest of St. Augustinegrass is the chinch
bug, although resistance to chinch bugs varies
somewhat among cultivars. For example, Floratam
and Floralawn have traditionally been considered
chinch resistant, but over time the insect has
overcome this and are now considered a pest to these
cultivars as well. St. Augustine Decline Virus
(SADV) is a major disease problem in some parts of
the United States but has not been identified as a
problem in Florida. Some cultivars are also
susceptible to gray leaf spot disease.

Cultivars

 

There are several cultivars of St. Augustinegrass
available for lawn use in Florida. The different
cultivars vary in their tolerances to environmental
stresses or their susceptibility to pests, so it is
advisable to check with your county Cooperative
Extension Service office for the best grass for your
location and needs.

Common and Roselawn

These are pasture types of St. Augustinegrass
that evolved in the 1800s. They produce a coarse,
open turf that is susceptible to chinch bugs, herbicide
damage, shade, and cold damage. They also have a
light leaf color and do not respond well to
fertilization. Avoid planting these cultivars if lawn
appearance is important.

Bitterblue

This is an improved variety selected in the
1930s. Bitterblue has a finer, denser texture and
darker blue-green color than common St.
Augustinegrass. It has improved cold tolerance and
good shade tolerance but is not resistant to chinch
bugs or gray leaf spot disease. Its tolerance to
atrazine is also lower than other varieties, making
weed control more difficult. Bitterblue can produce a
good lawn under proper management practices and
pest control.

Floratine

This is an improved selection from Bitterblue
that was released in 1962 by the Florida Agricultural
Experiment Station. It has finer leaf texture and a
denser and shorter growth habit that allows closer
mowing than common St. Augustinegrass. It is not
resistant to chinch bugs but tolerates light to moderate
shade. Floratine's other characteristics are similar to
Bitterblue's.

Floratam

Floratam is an improved St. Augustinegrass that
was released jointly in 1973 by the University of
Florida and Texas A & M. Floratam is the most
widely produced and used St. Augustinegrass in
Florida. It is a coarse-textured cultivar that has poor
cold and shade tolerance. It will thin in direct relation
to the amount of shade received. It grows vigorously
in the warmer, but has a relatively long period of
dormancy in north Florida and greens-up more slowly
in the spring than some cultivars. It has some degree
of chinch bug and SADV resistance, although new
strains of chinch bugs that can damage Floratam have
been identified. Floratam is tolerant of atrazine
herbicides when temperatures are below 85°F.

Palmetto

Palmetto was a selection from a Florida sod
grower in 1988. It was well received by sod growers
St. Augustinegrass for Florida Lawns 3
throughout the southeast, but, unfortunately, little
university research has been done to date on this
cultivar. It is often described as highly tolerant of
shade, drought, and cold, but no impartial evidence of
these claims exists at this time. It does exhibit a
shorter growth habit, similar to Jade, Delmar, and
Seville.

Raleigh

Raleigh is a cold-hardy cultivar released by
North Carolina State University in 1980. It has a
medium green color with a coarse texture. It is
susceptible to chinch bugs, but can be planted in
northern Florida due to its tolerance to lower
temperatures. It is also susceptible to brown patch
disease. During peak summertime heat, Raleigh has
been noted to yellow and to not grow as aggressively
as during cooler temperatures. Supplemental iron
applications can reduce this yellowing tendency.
Raleigh is best adapted to the heavier, organic, clayey
soils with medium to low soil pH in central and north
Florida.

Seville

Seville is a semi-dwarf, fine-leaved variety with
a dark green color and a low growth habit. It is
susceptible to chinch bug and webworm damage, but
resistant to SADV. Due to its compact growth habit,
Seville tends to be thatch-prone and shallow rooting.
Seville performs well in shade and full sun, but is
cold sensitive. Its cold tolerance is similar to
Floratine's. Being a semi-dwarf variety, Seville's
maintenance is different than taller growing varieties.

Floralawn

This cultivar was released in 1986 by the Florida
Agricultural Experiment Station. It is resistant to
SADV, chinch bugs, sod webworms and brown patch.
Like Floratam, it has poor shade and cold tolerance. It
is also coarse-textured. Floralawn should be grown in
mild environments in full sun to moderate shade
under low to moderate fertility.

Jade and Delmar

These two semi-dwarf releases are commercially
available as sod or plugs. Jade and Delmar have
improved shade tolerance, shorter internodes, a darker
green color, and better cold tolerance than Seville.
They should be mowed at 1 1/2-2 1/2 inches. Jade has a
finer leaf blade texture and better shade tolerance than
Delmar. Delmar has enhanced cold tolerance;
therefore, it can be grown in cooler regions of
Florida. Jade and Delmar are both susceptible to
chinch bugs, sod webworms, and brown patch
disease. These also have slow lateral runner growth,
thus, require longer periods for grow-in from plugs or
recovery from damage.

Maintenance of St. Augustinegrass

It is advisable to check with your local County
Extension office for cultivars best adapted to your
geographical area and uses. As emphasized
throughout the Florida Lawn Handbook, proper lawn
maintenance practices are the best means for avoiding
pest problems and obtaining a high quality lawn.

Establishment

The best time to establish St. Augustinegrass is
during the spring or early summer months. This
enables the grass to grow in before cooler weather
begins, when growth will be reduced. In south
Florida, establish St. Augustinegrass during winter or
spring. When establishing any grass, it is important to
provide irrigation more frequently than normal
recommendations call for. Frequent, short irrigations
throughout the course of the day will help the root
system to become established in the soil and become
viable. Mowing should not be done until the roots
have had a chance to peg down into the soil.. Vegetative
propagation means that plant parts with growing
points are used for planting rather than seeds. St.
Augustinegrass has stolons (aboveground stems) that
have areas of actively dividing cells at the nodes.
These areas are capable of generating new shoot
growth and are responsible for lateral growth of St.
Augustinegrass along the ground.

Sodding

Sodding will produce an instant lawn, as you
virtually cover the entire area to be planted with grass
material. Sod should only be laid over bare moist soil
with pieces laid in a staggered brick-like pattern and
the edges fitted tightly together to avoid any open
cracks. Rolling and watering thoroughly will insure
good contact with the soil for fast rooting. Sodded
areas should be watered at least twice per day with 1/4
inch of water until the sod is held fast (usually 2 to 3
weeks) to the soil by roots; then watering should be
reduced to an as-needed basis.

Sprigging

Sprigging is less expensive than sodding, but
does not produce an instant lawn as does sodding. It
is a labor-intensive way to cover a large area. Sprigs
contain nodes on stolons, which are planted
end-to-end in furrows 6 to 12 inches apart. Stolons
should be covered with soil, but leaf blades should be
left exposed. The soil should be tamped and watered
in thoroughly. Soil should be kept moist until new
stolons appear.

Plugging

A number of St. Augustinegrass cultivars are
available commercially as plugs. Sod also can be
made into plugs by cutting it into small squares.
Spacing of plugs varies from 6 to 24 inches. The
closer spacing provides full coverage in 3-6 months
and farther spacing covers in 6 to 12 months. Plugs
are placed in holes of the same size or in open
furrows and tamped into place. A thorough watering
completes the installation. The turf should then be
cared for like a sprigged lawn.

Fertilizing

Proper fertilization of any lawngrass is an
important component of the best management
practices of your home lawn. Fertilization and other
cultural practices influence the overall health of your
lawn, and can reduce or increase its vulnerability to
numerous stresses, including weeds, insects, and
disease.
 

It is advisable for homeowners to have soil tests
done annually. Your local Cooperative Extension
office has instructions and supplies for taking soil
samples and submitting to the Extension Soil Testing
Lab for analysis. In particular, phosphorous levels are
best determined by soil testing. Since many Florida
St. Augustinegrass for Florida Lawns 5
soils are high in phosphorous, little or no
phosphorous may be needed for satisfactory lawn
growth.
 

Maintaining a good quality lawn requires a
properly planned fertility program. An acceptable
quality St. Augustinegrass lawn can be grown with a
low to high level of fertility, depending on what the
homeowner wants. First, decide how much time and
effort can be spent on lawn maintenance. A lower
fertility lawn is best for those with little time to spend
on lawn care. A high fertility lawn may be better
suited to those who desire a manicured appearance for
their yard. This type of maintenance will require more
time and money for lawn care.
In general, two weeks following spring
regrowth, apply a complete fertilizer such as 16-4-8 at
the rate of 1/2 (water-soluble) to 1 (slow-release)
pound of nitrogen per 1000 square feet. The three
numbers refer to percent nitrogen, phosphorous, and
potassium, respectively, in the bag. For example, a
50-pound bag of 16-4-8 contains 16% nitrogen or 8
pounds total nitrogen. This bag will fertilize 8000
square feet at the rate of 1 pound of nitrogen per 1000
square feet at this rate. Higher fertilization rates will
produce a faster buildup of thatch than lower rates.
High rates of fertilizing can also encourage insect
damage to the turf. Additionally, the necessary
amount of mowing and watering increases with the
amount of fertilizer.
 

University of Florida guidelines for lawngrass
fertility show a range of fertilizer rates over which a
particular species may be successfully grown for
various areas of the state. These ranges are included
to account for individual homeowner preferences for
low-, medium-, or high-input grass. Additionally,
localized microclimate effects can have a tremendous
effect on turfgrass growth, and a range of rates
provides more opportunity to allow for these
environmental variations. An example of this would
be a typical home lawn that is partially shaded and
partially sunny. The grass growing in the shade
should receive lower rates of fertilizer than that
growing in full sun. The guidelines are also separated
into three geographical locations statewide as
indicated in Table 2 and Table 3 . All rates are in
pounds of nitrogen per 1000 square feet. For
questions on how to apply these amounts, refer to the
section in this book entitled Florida Fertilization.
Fertilizer should be applied to St. Augustinegrass
in 2 to 6 application from spring greenup through
fall. Do not apply nitrogen too early in the growing
season, particularly in north Florida, or subsequent
frosts may damage the grass. Likewise, don't fertilize
too late in the year, as this can slow regrowth the
following spring. If applying water-soluble forms at
the lower application rate, it will take more
applications to apply the total amount of fertilizer
needed for the year than if applying a slow-release
form.
 

On high pH (>7.0) soils or where high pH water
is applied, yellow appearance may be an indication of
iron or manganese deficiency. For iron deficiency,
spray ferrous sulfate (2 ounces in 3 to 5 gallons of
water per 1000 square feet) or a chelated iron source
(refer to the label for rates), to temporarily enhance
color. Iron applications every 6 weeks will help
maintain green color and, unlike nitrogen, will not
promote excessive top growth. Lower the soil pH by
applying 15 pounds of elemental sulfur per 1000
square feet prior to grass establishment. Once the
grass is established, up to 5 pounds of elemental
sulfur may be added per 1000 square feet, it if is
immediately irrigated in to prevent burn. Using
ammonium nitrate or sulfate as a fertilizer source will
also help to temporarily reduce soil pH. Apply
manganese as a fertilizer with micronutrients or as
straight manganese sulfate (MnSO4) bimonthly at
0.41 pounds per 1000 square feet (18 pounds per
acre) to relieve deficiency symptoms if present.

Mowing

 

Proper mowing practices are necessary to keep
any lawn healthy and attractive. Under high levels of
management, St. Augustinegrass can be maintained at
2 inches if the lawn is mowed at least weekly during
the growing season. Mowing at this height and
frequency requires more fertilizer and water to
maintain an attractive lawn. Also, low cutting heights
and high maintenance levels can predispose the turf
to many pest problems. Under moderate or low levels
of management, St. Augustinegrass should be cut at a
height of 3 to 4 inches. This height will help
the grass develop a deep root system and give a better
appearance to the turf. Mowing frequency under
moderate or low management should be adjusted to
the amount of growth. No more than one-third of the
leaf blades should be removed with any mowing.
Low mowing heights can cause problems in turf
quality. Repetitive low mowing reduces the density
and vigor of St. Augustinegrass and can lead to weed
problems. The mowing height should be increased to
4 inches during periods of moisture stress or if the
grass is growing in shade. Newer semi-dwarf
varieties have a lower growth habit, and should be
mowed at 1 1/2 to 2 inches for optimum quality.
Mowing too infrequently and watering improperly
can cause a thatch buildup. The chapter entitled
"Thatch and its Control in Florida Lawns" in this
publication has more information on thatch.
Either a rotary or reel mower can be used on St.
Augustinegrass. It is important to keep the blades
sharp and well-adjusted to get a clean cut. Dull blades
will give the lawn a brownish cast, because a ragged
cut shreds the leaf blades rather than cutting them.
During the growing season blades should be
sharpened on a monthly basis.
 

Grass clippings can be left on a lawn that is
mowed at the proper height and frequency. Under
these conditions, clippings do not contribute to the
thatch layer. Clippings should be left on lawns
maintained with low to moderate fertility levels to
help recycle nutrients. If clippings are excessive (e.g.,
clumping occurs), let them dry out and then disperse
them.

Watering

The best way to irrigate an established lawn is on
an as-needed basis. Grass blades will begin to wilt
(e.g., fold, turn bluish-green in color and not recover
from traffic or footprints) as the moisture begins to
be depleted in the soil. If 30 to 50% of the lawn
shows signs of slight wilting, it is time to irrigate
with 3/4 - 1" of water. The turf will fully recover
within 24 hours. The turf should not be watered again
until it shows signs of wilting. This irrigation
schedule works for any soil type and environmental
condition. For further information on recommended
watering practices see the chapter in this publication
entitled "Watering Your Florida Lawn." Proper
watering practices will help maintain a lawn that
requires less mowing and has little thatch buildup.
Proper watering will also help develop a deep root
system and be less susceptible to damage by pest and
environmental stresses. If the diseases brown patch or
gray leaf spot are a continuous problem, excessive
watering and nitrogen fertilization may be
responsible. Certain weeds (like pennywort and
nutsedge) also thrive in soils which are continuously
wet. Regulate these management practices closely to
reduce disease and weed severity.
Irrigation on an as-needed basis is an efficient
way to water any grass, providing that the proper
amount of water is applied when needed. Normally,
fall through spring is the driest period of the year.
Therefore, irrigation is required to replace water lost
via evapotranspiration. Apply enough water to rewet
the soil rootzone and then wait until the turf shows
signs of drought (e.g., wilting) again before the next
irrigation (usually every 7 to 14 days in winter, 3 to 4
days in April-May, depending on soil type and
maintenance practices). For most Florida soils, no
more than 3/4 inch of water is necessary to rewet the
upper 8 to 12 inches of the soil profile, which is
where the majority of the roots are. To determine
rates from a sprinkler system, place several coffee
cans throughout the irrigation zones to find out how
long it takes to apply 3/4 inch of water. Irrigation is
needed when leaf blades begin to fold up, to actually
wilt, turn blue-gray in color, or when footprints
remain visible on the grass. The length of the
irrigation period to apply this 3/4 inch can stay
constant year round; only the frequency between
irrigations should change. Therefore, irrigation
programs set by automatic timers do not need to
operate on a daily schedule. They need only to operate
after the turf begins to show signs of drought and then
be programmed to apply an average of 3/4 inch of
water. Overwatering encourages nutrient leaching,
increased pest problems, shallow rooting, and, of
course, water waste.

Information provided by the University of Florida's IFAS Extension