Zoysia grasses for Florida lawns
Zoysia grasses (Zoysia spp.) were introduced into the United States from the Orient and provide attractive turf throughout much of the United States. Several species and varieties are used for residential and commercial landscapes, athletic fields, and golf course tees, fairways, and roughs.
An established, well-managed zoysia grass provides a high quality turf, but zoysia grasses generally require a high level of maintenance. Improvements in zoysia grass varieties, however, are a major objective of many turf grass breeders.
These improvements are aimed at maximizing the positive attributes of zoysia grass, while minimizing the disadvantages.
Zoysia grasses are adapted to a variety of soils and have good tolerance to shade, salt, and traffic. They provide an extremely dense sod that resists weed invasion. Once established, the slow growth of some zoysia grass varieties is an advantage because mowing frequency is reduced. When properly maintained, however, zoysia grasses make excellent turf.
The improved zoysia grasses must be propagated vegetatively and some varieties are extremely slow to establish. For some varieties, two growing seasons may be required for coverage when propagated by plugging or sprigging; others establish much more rapidly. All zoysia grasses form a heavy thatch that will require periodic renovation.
Other disadvantages of the older varieties include slow recovery from damage, poor growth on compacted soils, high fertility requirements, and poor drought tolerance. Some varieties are also prone to damage by nematodes, hunting billbugs, and several diseases. Zoysia grass also tends to form shallow roots and is weakened when grown in soils low in potassium. Due to toughness of leaves and stems, a reel mower will provide the best cut.
This species was introduced into the United States in 1895 and is commonly called Japanese or Korean lawn grass. It is a very coarse textured grass with hairy, light green leaves. Of all the zoysia grasses, this species has a faster growth rate and exhibits excellent cold tolerance.
Zoysia japonica is the only zoysia grass for which seed is commercially available, however, the seeded varieties generally do not produce as high quality turf as do the vegetatively propagated varieties. They can be used for lawns or general turf areas where convenience of establishment by seed is more important than quality. Additionally, hunting billbugs and nematodes cause considerable damage to some varieties of this lawn grass.
Belaire is an improved Zoysia japonica developed in Maryland by the USDA and released in 1985. It is noted for its excellent cold tolerance and medium green color. Compared to 'Meyer', 'Belaire' has a more open growth habit, coarser leaf texture and faster establishment rate. Brown patch disease may be a problem for this variety.
Crowne is a coarse-textured vegetatively propagated clone of Zoysia japonica released by Texas A&M University. 'Crowne' is noted for its tolerance to low water use requirements, cold hardiness and rapid recuperative ability. It was released for used on home lawns, industrial parks, highway rights-of-way, and golf course rough areas. As with 'Palisades', nematode susceptibility is not known for this variety.
El Toro is also an improved Zoysia japonica released in 1986 from California. It resembles 'Meyer' but has a quicker establishment rate, improved cool-season color, better cold tolerance, and less thatch buildup. 'El Toro' is also reported to have early spring green-up, more shade tolerance, and improved resistance to rust disease.
Empire zoysia grass is a native proprietary selection of Zoysia japonica. It it said to be dark green in color with a wide leaf blade and open growth habit. It has performed well in sandy and clay soil types with aggressive growth from its stolons and rhizomes, but can be mowed with a standard rotary mower due to its broader leaf and open growth habit.
Empress is another native proprietary selection of Zoysia japonica, however, unlike 'Empire', this grass was selected for its fine bladed texture, tight growth habit, and green color. 'Empire' is best suited for applications where a fine, small leaf, soft textured turf is desired such as home lawns, golf courses, parks, and sports fields.
Meyer zoysia grass, also called Z-52 or 'Amazoy', is an improved selection of Zoysia japonica released in 1951. 'Meyer' is the zoysia grass often advertised as the "miracle" grass in newspapers and magazines and has long been the standard zoysia grass in use. It has a deep green color, medium leaf texture, and spreads much faster than other varieties, although it produces few rhizomes.
'Meyer' makes an excellent turf once established. It is less shade tolerant than 'Emerald', but is one of the most cold tolerant zoysia grasses. Hunting billbugs and nematodes pose serious problems with 'Meyer', limiting its use in Florida.
Palisades is an improved Zoysia japonica that forms a medium to coarse-textured turf. Released by Texas A&M University, 'Palisades' produces a vigorous regrowth from stolons and rhizomes and is noted for its good winter hardiness, tolerance to low mowing, and good to excellent shade tolerance. It is said to be a low water user and has good salt tolerance.
'Palisades' is being marketed for home lawns and for use on golf courses. One concern with 'Palisades' is the lack of research information on nematode susceptibility.
Also called Manila grass, this species was introduced into the United States in 1912 from Manila (hence the name). It produces a finer and denser turf than Zoysia japonica but is less winter-hardy and slower growing. Manila grass resembles bermuda grass in texture, color and quality and is recommended for a high-quality, high-maintenance turf where a slow rate of establishment is not a disadvantage. Some varieties of Zoysia matrella are highly susceptible to damage by nematodes.
Cashmere is a 1988 release from Pursley Turf Farms located in Palmetto, Florida. It is dark green, has a fine leaf texture and forms a dense turf. Its shade tolerance is not fully known, but it does lack cold hardiness, and is thus best adapted to the lower southern region.
Cavalier is another fine-textured Zoysia matrella cultivar and is appropriate for home lawns, sports fields, and golf course fairways and tees. A long-leafed variety, it is said to make a very attractive turf, especially during summer. It is rated as having good shade tolerance, good salt tolerance, and excellent fall color retention.
In trials conducted at Texas A&M at Dallas, 'Cavalier' showed good resistance to fall army worms and moderate resistance to tropical sod web worms. 'Cavalier' has done well in trials in Texas, the Midwest and mid-Atlantic regions, however, limited research has been conducted in Florida on this grass.
Diamond is an improved Zoysia matrella that is vegetatively propagated. It was released from Texas in 1996. 'Diamond' is distinguished from other zoysia grasses by its fine texture, excellent salt and shade tolerance, and faster growth. It performs best when mowed at a height of 1/2-inch or less. In fact, 'Diamond' has been planted on several experimental golf greens mowed at 1/4-inch or lower. Like other zoysia grasses, it has poor cold tolerance, which may limit its use in northern parts of the state and it is highly susceptible to tropical sod web worms.
Also called Mascarene grass or Korean velvet grass, this species is the finest textured and most dense zoysia grass available. It has good wear tolerance but poor cold tolerance, and is only adapted to the central and southern areas of the state. It also produces an excessive thatch, giving it a puffy appearance.
Zoysia grass Hybrids
Emerald zoysia grass is a selected hybrid between Zoysia japonica and Zoysia tenuifolia developed in Tifton, GA and released in 1955. This hybrid combines the winter-hardiness, color, and faster growth rate of one parent with the fine texture and density of the other parent. 'Emerald' resembles Manila grass in color, texture, and density, but is faster-spreading and has a wider adaptation.
'Emerald' zoysia grass is highly recommended for top quality lawns where time and money allow for adequate maintenance. 'Emerald' produces an excessive thatch layer and is susceptible to dollar and leaf spot. Brown patch disease also can occur.
Zoysia sinica--A new species for turf?
Seashore zoysia grass (not to be confused with Seashore paspalum) is an obscure species that was previously not considered suitable for turf. However, breeding efforts have produced an improved cultivar 'J-14'. It most closely resembles Zoysia japonica as far as leaf texture, color, density, and general appearance are concerned.
One major difference is that the seed for Seashore zoysia grass is much easier to handle and appears to propagate better. 'J-14' is currently being tested at Gainesville and Milton.
With one exception, zoysia grasses must be planted vegetatively, by sod, plugs, or sprigs. Zoysia japonica is the only species for which seed is commercially available. Success with any propagation method is highly dependent on proper soil preparation.
Establishing zoysia grass from seed is increasing in popularity. The seed, however, is extremely sensitive to light and cannot be covered with soil. Consequently, areas to be established by seed need to be covered with some type of erosion cloth to reduce any surface disruption caused by rain or irrigation.
After seeding, frequent, light irrigations are necessary to keep the soil moist and encourage germination. Maintain this moisture regime until the planted area is completed covered.
Sodding will produce an instant turf, as the entire area to be planted with grass material is covered. 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 a 1/4 inch of water until the sod is held fast (usually 2 to 3 weeks) to the soil by new roots; then watering should be reduced to an as-needed basis.
Because of the relatively slow establishment rate of zoysia grass, plugs are usually planted on 6- to 8-inch centers. This means that plugs are planted every 6 inches in a row and rows are spaced 6 inches apart. Even with 6-inch spacing, at least one full season will be required for complete coverage; longer for some varieties.
Plugs should be tamped firmly into the soil and watered in. During grow-in, the soil should be kept moist until the grass is well rooted. Extra attention to weed control is necessary during this type of establishment.
Planting zoysia grasses by sprigs is a laborious, but effective, method of establishment. Fresh sprigs with at least two or four nodes should be planted in rows that are 6 inches apart. Plant the sprigs end-to-end or no more than 6 inches apart in the row, and cover them with soil about one to 2 inches deep, leaving part of each sprig exposed to light. A roller can be used to press sprigs into the soil. Soil must be kept moist until plants initiate new growth and the area is completely covered.
Proper fertilization is an important component of the best management practices of your turf. Fertilization and other cultural practices influence the overall health of the turf and can reduce or increase its vulnerability to many stresses, including weeds, insects, and disease.
Having soil tests done annually to determine the exact fertility need is advisable. Your local UF Cooperative Extension Service county office has instructions and bags for taking soil samples and submitting to the UF Extension Soil Testing Lab for analysis.
These tests form the basis for your turf fertility program and recommendations from the soil tests should take precedence over recommendations given in publications or on fertilizer bags. In particular, phosphorous levels are best determined by soil testing. Since many Florida soils are high in phosphorous, little or no phosphorus may be needed for satisfactory turf growth. The exception to this may be during establishment.
In general, two weeks following complete spring green-up, apply a fertilizer at the rate of 1/2 (water-soluble) to 1 (slow-release) pound of nitrogen per 1000 square feet. The three numbers on a fertilizer bag refer to percent nitrogen, phosphorus, 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. To look their best, zoysia grasses require frequent fertilization. They should receive 3 to 6 lbs. of nitrogen during the growing season in most situations.
University of Florida guidelines for lawn grass 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 micro-climate effects can have a tremendous effect on turf grass 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 1 and Table 2. All rates are in pounds of nitrogen per 1000 square feet.
Fertilizer should be applied to zoysia grass in 3 to 6 applications 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 fertilizer form.
If fertilized as recommended, zoysia grasses will require frequent mowing (e.g., weekly) during the summer to look their best. Zoysia japonica should be mowed every 7 to 10 days, or when it reaches a height of 3 to 4 inches. It should be mowed at a height of 2 to 3 inches with a rotary mower. 'Meyer' zoysia grass looks best when cut at 1 to 2 inches every 10 to 14 days, or when it reaches a height of 2 to 2.5 inches, using a reel mower.
'Emerald' and Manila grass should be cut with a reel mower at 1/2 to 1 inch every 10 to 14 days, or when they reach a height of 3/4 to 1.5 inches. Because zoysia grass leaves are very coarse, they can be quite difficult to mow. A sharp, well-adjusted rotary or reel mower should be used.
Zoysia grasses require watering especially if parasitized by nematodes, which greatly restrict the root system. During prolonged droughts, watering zoysia grass every other day may be necessary. Irrigation on an as-needed basis is an excellent way to water any grass, provided the proper amount of water is applied when needed; not at a later or more convenient time. When using this approach, water at the first sign of wilt and apply 3/4 inch water per application.
Information provided by the University of Florida's IFAS Extension