|
Extension Bulletin No. 9
June 1992
VIRGIN ISLANDS
HOME LAWNS
Examples of described grosses on St Cro.c
UNIVERSITY OF THE VIRGIN ISLANDS
Cooperative Extension Service D. S. Padda, Director St. Croix, U.S. Virgin Islands
VIRGIN ISLANDS
HOME LAWNS
by
Clinton George
UVI Extension Program Leader,
Agriculture and Natural Resources
Extension Bulletin No. 9
June 1992
Copies of this bulletin available from:
COOPERATIVE EXTENSION SERVICE
UNIVERSITY OF THE VIRGIN ISLANDS
RR 2, BOX 10,000, KINGSHILL, ST. CROIX, USVI 00850
(809)778-0246
Editor
Robin Stems
Illustrations
Toni Thomas
Vrgin Islands Lawn Grasses Is published by the University of the Virgin Islands Cooperative Extension Service, D.S. Padda, director.
Contents of this publication constitute public property. No endorsement of products or firms is intended, nor is criticism implied of those not
mentioned. Issued by the Virgin Islands Cooperative Extension Service and the U.S. Department of Agriculture in furtherance of the acts of May
8 and June 30,1914. Extension programs and policies are consistent with federal and state laws and regulations on non-discrimination regarding
race, color, national origin, religion, gender, age, disability or gender preference.
VIRGIN ISLANDS HOME LAWNS
INTRODUCTION
It is difficult to imagine what homes in the Virgin Islands would look like without lawns. They
provide uniformity and beauty to our overall landscape, help control erosion and dust, and reduce noise
and glare. Lawns have a significant overall cooling effect on the environment. And, of course, they
provide surfaces for our youth to play on.
To have a good lawn you must consider: I) choice of grasses; 2) construction of the lawn how
the seedbed is prepared; 3) planting the lawn how and when it should be planted, and 4) maintenance,
including fertilizing, mowing, watering, and controlling weeds, diseases and insects.
LAWN GRASS SELECTION
The correct species and variety for your lawn should be
selected carefully. This requires knowing where the lawn will be used,
how it will be used, and what appearance and maintenance level will "
be acceptable. Because each lawn grass species has good and bad
features, learn the strengths and weaknesses of each of the species to
choose the one best suited to our climatic and soil conditions.
The following are descriptions of some common lawn grasses
adaptable to Virgin Islands conditions. Included are statements on how
they grow, where they grow best, their requirements, and how to
establish them.
It should be noted that planting material for vegetatively
propagated lawn grasses (sod or plugs) is not easily available in the
Virgin Islands.
Hurricane Grass
HURRICANE GRASS (Bothriochloo pertusa)
This is by far the predominant lawn grass in the Virgin Islands. It is a hardy, aggressive, native grass
which stands up exceptionally well to wear. The agronomic characteristics of hurricane grass have not
been thoroughly researched, but practical experience with it throughout the territory suggests it
performs satisfactorily and is easily established by seeding. It has been considered a successful turf grass
at the University of the Virgin Islands campuses, the golf courses on St. John (Caneel Bay) and Virgin
Gorda (Utde Dix Bay).
Hurricane grass has a dense thatch and apparently is drought, salt, disease and insect resistant.
It does not tolerate dense shade, but persists well in moderate shade if regularly mowed. The main
disadvantage of Hurricane grass is that frequent mowing is required to remove unsightly seed heads.
BERMUDA GRASS (Cynodon dactylon)
This grass is moderately tolerant of heat, poor soil, alkalinity, salt and heavy traffic. It is fairly
tolerant to dry conditions. Insect and disease resistance are generally good. However, Bermuda grass
also requires frequent mowing and nitrogen fertilization. It needs full sun for best performance and
spreads rapidly.
Common Bermuda grass makes a fairly presentable lawn
when given reasonable care. This grass is established by seeding.
Common Bermuda grass needs to be mowed often to a I-inch
height to prevent formation of seed heads.
Hybrid Bermuda grasses are often used for high-quality
lawns. They are only established vegetatively so they must be
sodded or planted from sprigs or plugs spaced 6 to 12 inches apart.
The hybrids also require more nitrogen fertilization. Tifway,
Tiflawn, and Tif green are three of the most common hybrid
varieties.
BAHIA GRASS (Paspalum notatum) .. *
This is a low-growing perennial that spreads by short heavy
runners. It is established by seeding. In areas of poor soils bahia grass
will make a reasonable substitute for Bermuda grass. It tolerates Bermuda Grass
little salt but is relatively free from insects and diseases, and is
somewhat drought and wear resistant This grass needs to be mowed weekly during the rainy season
and every other week during the dry season to 2 inches high with a sharp mower to cut off tough seed
heads.
ZOYSIA GRASS (Zoysia species)
If you want a smooth, even-textured lawn that is really tough, this is the grass for you. It
withstands wear, tolerates partial shade and is subject to little disease and insect damage. It gets by on
normal watering, does not take over planted beds, and is thick enough to crowd out weeds and other
grasses. However, there are two drawbacks: Zoysia grass is difficult and slow to establish by seeding.
Plugs may take at least a full year to cover an area completely, even when planted close (6 inches apart).
This grass needs to be mowed about 3/4 to I-inch high.
ST. AUGUSTINE GRASS (Stenotaphrum secundatum)
This grass thrives in both sunny and partial shady locations. It makes a thick sod, is coarse in texture,
and tolerates traffic fairly well. Best growth is with ample water in a fertile, well-drained soil. But St.
Augustine grass is hardy and will persist in salty soils.
Unfortunately, St Augustine grass is susceptible to brown patch, heat spot, chinch bugs and
white grubs. This grass is not easily established by seeding; you will need to sod or plant from sprigs
or plugs at 12 inches apart. Mow to a height of 2 or 3 inches. St. Augustine eventually gets very thick
and must be dethatched on a regular basis.
DESCRIPTIONS OF SOME WARM SEASON LAWN GRASSES
Grm h id Rate of Drought Smit Shade Wear Teture Maintenance
Variety Spread Tolerance Tolrance Tolerance Resistence
Hurricane Seed Rapid Very Good Very Good Fair Very Good Fine Heavy
(Loca.
Bermuda Seed. Rapid Very Good Very Good Poor Very Good Fine Heavy
(Common Vegetative
and
Improved)
Bahbi Moderate Moderate Good Poor Good Good Medium Lght
Course
St. Vgetative Moderate Good Very Good Very Good Fair Mediurn Heavy
Augustine Course
Zoysa. Vegetative Very Slow Fair Very Good Good Very Good Medium Heavy
Fine
Cenipede Seed Moderate Poor Poor Good Poor Medium Lght
Course
LAWN SITE PREPARATION
Proper preparation of the lawn planting site is very important in establishing a quality lawn. It
would be great if topsoil were always stockpiled at the start of construction and then replaced when
the house is finished. Unfortunately, many sites are stripped bare and you end up with poor soil, or
the soil may have been poor to begin with. This may be the case in certain areas in the V.I. where caliche
is prevalent In these extremes cases, it may be advisable to bring in good quality topsoil. Usually,
however, the addition of organic material and fertilizer to existing soil is less expensive.
Weeds are a good indicator of soil quality. If you have a lush crop of various types of weeds,
your grass should grow just as well. If the neighbors' yards are thriving, this is also a good indicator.
But be sure to find out if they had to make extensive modification to the land and soil to get the grass
to grow well.
In the case of absence of vegetation in nearby landscapes, it is difficult to tell what your soil is
like by just looking at it. The safest way to determine soil fertility is to have your soil tested. The
Cooperative Extension Service offers a soil testing service free of charge to all V.I. residents and provides
two gardener's factsheets on soil testing. The soil test results give specific recommendations as to what
should be added to your soil before planting, The soil test also determines the pH of your soil (acidity
or alkalinity). A pH value of 6.0 to 7.0 is desirable for most lawn grasses. However, most soils in the
V.I. have a high pH value (above 7.0). This ties up some nutrients, especially the trace elements (see
Gardener's Factsheet # 16).
Whether you are planting a new lawn or replanting an old ME
one, certain practices have to be followed in preparingthe site for
planting. Remove all debris, brush, rocks and weeds before
grading the site. Especially in hard clay soils, plowing or spading
followed by disking and hand raking are the best methods of
preparing the soil. Hand raking is necessary to level the soil and
to prevent the formation of depressions and hollows where
water might accumulate. The site should be gently sloped away /
from the home so that water will drain away. Degree of slope
should be slight, because steep slopes make grass difficult to
establish and mow. Other ground cover can be planted if the
slope is too steep for grass.
Based on your soil test results, a complete fertilizer
should be applied to the soil and raked lightly into it just prior to ,
planting. In general, use about ten to 20 pounds of a 10-10-10 or
an equivalent fertilizer per 1,000 square feet unless a test has St Augustine Grass
shown that the soil needs a larger or smaller amount Mix the
fertilizer thoroughly into the top three to five inches of the soil
where the roots will feed.
Some soils require additional treatment. Ifthe soil is gravelly or mostly heavy clay, you may need
to incorporate soil additives to improve its organic-matter content or texture. Amendments such
as peat, composts, manures and untreated wood shavings are most commonly available. All such
materials are useful, so choose the one most available and least expensive. All are relatively easy to mix
with the soil and should be free of weed seed. On heavy clays, an amendment such as gutter or builder's
sand can also beadded. Add abouttwocubic yards forever 1,000squarefeet of lawn area. It is essential
that any soil amendment be well incorporated into the soil, preferably with a mechanical device like a
Rototiller. Mix to a depth of at least six inches.
The last step before planting is the final grading. The site should be as level and smooth as
possible. The planting area can be raked or dragged with a steel mat until smooth or leveled by grading
equipment. Remember, the more level the site, the more attractive the lawn and the easierthe mowing.
PLANTING YOUR LAWN
There are two methods of establishing a lawn: seeding and vegetative propagation. The latter
refers to planting material that are multiplied asexually (sods, plugs or sprigs). Seeding is usually the most
economical method of planting a lawn, but this method requires a longer period of time for
establishment; and not all lawn grasses can be grown from seed.
Seeding
Seeding is the easiest method of planting a lawn, but success will depend on several factors:
quality of seed proper seeding time, rate and method of seeding.
Before you purchase your seed, examine the analysis tag on the container to be sure you are
getting a good quality seed. Federal laws require that tags give the percentage of each grass seed in the
container, the purity and germination, and the date of test.
The best time to seed a lawn in the Virgin Islands is at the beginning of the rainy months (in the
fall). This is when conditions are most favorable for germination and growth.
Seeding rates are shown in the chart below. Rates vary with species and variety of grass. For
example, only 1-2 pounds are needed to seed 1,000 sq. ft. of Bermuda grass. In contrast, bahia grass
seed is larger and requires 5-10 pounds per 1,000 sq. ft. to produce adequate cover.
Grass seed may be planted by hand or with a mechanical seeder. However, to produce a more
uniform distribution, apply your seed mechanically using a rotary seeder. Another practice thatwill help
you obtain a more uniform distribution is to mix the seed with a convenient carrier such as gutter or
builder's sand. It is very important that you lightly cover the freshly sown seed by hand raking or by
dragging with a brush or mat. On slight slopes mulching with a light covering of weed-free straw or
hay will help hold moisture and prevent washing of the seed during watering or rainfall.
New seedlings should be kept moist until well-established. Once seeds have begun to
germinate, they must not dry out or they will die. Avoid saturating the soil: excessive moisture will float
some seeds to the surface which could easily be washed away. Also, too much water greatly increases
the chances of fungus diseases.
Vegetative Planting
Seeds of some grasses are not available or do not produce seedlings that are true type (identical
to parent species). Such grasses must be planted vegetatively. Vegetative planting is simply transplanting
large or small pieces of grass. Solid sodding means completely covering the seed bed with square or
rectangular pieces of grass. Plugging or sprigging refers to planting of pieces of sod or even individual
stems or runners called stolons. Unless good quality stock/grass is available, and complete coverage
is needed immediately, the expense of sodding is seldom justified.
PLANTING YOUR VIRGIN ISLANDS LAWN
Methods Available
Grass Seed Vegetative Ra Per 1.000 sq. ft.
Propagation
Hurricane Yes Sprigs, Plugs. Sod I 2 Ibs.
Bermuda:
Common Yes Sprigs, Plugs, Sod I 2 Ibs.
All Others No Sprigs, Plugs, Sod 6 12 Inches apart
Bahia Yes Sod 5 10 Ibs.
St. Augustine No Sprigs. Plugs. Sod 6 12 inches apart
Zoysia:
Z Jopon a Yes Sprigs. Plugs, Sod 1/2- I Ib.
All Others No Sprigs, Plugs, Sod 6 12 inches apart
Centipede Yes Sprigs, Plugs. Sod I 2 Ibs.
MAINTAINING YOUR LAWN
Lawns require regular water, plant food, mowing and pest control in order to maintain a healthy
and attractive appearance. Neglecting any one of these practices may result in an unpleasant looking
area around your home that was once your lawn.
In the Virgin Islands, because of low and uneven distribution of rainfall, supplementation of
deficient rainfall with water from another source is often necessary in order to produce a better quality
lawn. Since supplemental water is a scarce commodity in our islands, conditioning your lawn for
upcoming dry weather may be beneficial.
First of all, you should not water your lawn until the grass shows signs of wilt. Spots in the lawn
that turn color, footprints that remain in the grass long after being made, and leaf blades folded in half
lengthwise are all indicators that the lawn needs water. When you notice any of these conditions, apply
enough water to wet the soil thoroughly. Avoid watering the lawn lightly at frequent intervals; this
causes shallow growth of grass roots and stimulates growth of weeds. Clay soils which are prevalent
in the Virgin Islands require infrequent, thorough waterings. This enables the root systems to develop
and grow deeper into the soil. The deeper-rooted the grass, the better conditioned the lawn will be
to dry weather.
Understanding plant responses to nitrogen and
potassium fertilization is helpful in maintaining a healthy-looking
lawn. Shoot growth is enhanced and root growth reduced by
excessive nitrogen. Leaf blades become lush as nitrogen
fertilization increases. Conditioning your lawn for dry weather
can only be accomplished by applying just enough nitrogen to
obtain a small but continuous amount of growth.
Potassium fertilization can help lawn grass increase its
tolerance to stress. Potassium promotes increased root growth
and thicker cell walls. Lawn grass requires potassium in nearlythe
same amount as nitrogen. Other macro and micro-nutrients
should be kept at recommended levels for optimal growth. An
annual soil test is helpful for monitoring nutrient levels.
Do not apply fertilizer, particularly an inorganic fertilizer,
when the grass leaves are wet Water the lawn immediately after
Zoysia Grass applying fertilizer to wash the fertilizer off the leaves and prevent
burning.
Fertilizer mixtures that contain both organic and inorganic material are beneficial in maintaining
a healthy lawn. For example, organic nitrogen may cost more per unit of actual nitrogen than inorganic
nitrogen, but it releases its nutrient value to the grass more slowly, and thus gives more uniform
stimulation to the grass over a longer period.
Proper mowing is one of the most important factors contributing to an attractive lawn. It can
"make or break" the lawn regardless of the type of grass or how well it is otherwise maintained.
Optimum cutting height is determined by the growth habit of the grass and texture (width and
length of leaves). Mowing too lowweakens the grass and causes the sod to thin out, encourages invasion
of weeds, makes the grass more susceptible to pests, and can eventually cause the lawn to die. Mowing
too high produces a ragged, unattractive lawn and encourages build-up of thatch, a layer of plant debris.
Frequency of mowing is determined by climatic conditions. For example, during the rainy
season when grasses grow very fast, they must be mowed often. During the drier months, growth is
slower and mowing is needed less often.
Natural rate and type of growth also affects mowing frequency. Rapid growing grasses like
Bermuda grass must be mowed more often than slow growing grasses such as Zoysia and Bahia grass.
Suggested mowing heights and frequencies for various lawn grasses in the Virgin Islands are listed below.
Pest control on lawns should be done with a great deal of care because pesticides can add extra
stress through chemical damage. Once a pest problem has been diagnosed, treat it promptly following
recommendations from our Extension Pest Management program (809-778-0246).
SUGGESTED MOWING HEIGHTS AND FREQUENCIES
For Lawn Grasses in the Virgin Islands*
Grass Height (inches) Frequency (days)
Hurricane 1/2 I 7- 10
Bermuda:
Common 1/2 I 7- 10
All Others 1/2 3/4 7- 10
Bahia 2-3 10- 14
St. Augustine 2 3 7- 10
Zoysia 3/4- I 10 14
Centipede I 1/2 2 10 14
*These are general guidelines under normal weather conditions.
Digitally signed
UVI Library Lrary
i DN c=UVI
LJV I Li1. y L brary, c=US
Date 2002 06 09
09 25 41 -08'00'
|
