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The Honolulu Advertiser
Posted on: Friday, October 26, 2007

Ground cover can be better than turf grass for nice lawn

By Jay Deputy

Looking to create a lawn? Turf grass may not always be the best choice especially if the area is shaded (most turf grasses don't thrive in shade) or on a slope that makes frequent mowing unsafe or impractical. That's when ground cover is a good option.

A ground cover is a reasonably low-growing, attractive, evergreen (usually a broad leaf) plant used as a grass substitute for areas that would otherwise have no vegetation. Ground covers also soften architectural features by providing textural patterns and color. Some also are useful as edging for walks and ornamental beds.

What to consider when choosing a ground cover: location, purpose and degree of maintenance.

Shady areas present a special problem, as many ornamentals need direct sunlight for at least part of the day. In this case, a shade-tolerant species is essential no amount of fertilizer or water can replace sunlight.

While it's true that most ground covers don't need as much attention as grass, they aren't maintenance-free. For example, vining types need to be trimmed to keep them from invading neighboring areas. They are not recommended for use as borders or under shrubs and small trees (for that, use clumping types).

Mondo grass (which is actually a member of the lily family) is one of Hawai'i's more popular ground covers. The most commonly used species is Ophiopogon japonicus, which has several varieties. All tolerate full sun but do best in moist soil and are partial to full shade. Plants grow in tufts that consist of grass-like basal leaves 1/16 to 1/4 inch wide and up to 18 inches long, depending on the variety. Mondo spreads by sending up shoots from underground runners and tuberous roots. Loose organic soil is the best medium for rapid growth of new shoots.

Most popular is common mondo grass, a good choice for large shady locations. It forms clumps of dark green needle-like foliage 12 to 15 inches long and the tufts can be several inches in diameter. With good irrigation and rich organic soil, common mondo will spread over a large area.

Two variegated varieties can be used for accent. The showy Silver Mist, with stark white and green leaves about 10 inches long, is often used in very shady areas. O. jaburan Variegatus, a.k.a. Aztec grass, looks similar to a longer-leaved Silver Mist and does well in full sun and under drier conditions.

Two low-maintenance dwarf varieties are best used as border plants or between stepping stones. Nanus, commonly called dwarf mondo, has 3-inch leaves in tight tufts and Kyoto dwarf, commonly called super dwarf mondo, has short, tight tufts less than 1 1/2 inches long. Both spread slowly, if at all, and grow best in full shade and do not tolerate poorly drained or waterlogged soil. Be very careful if applying chemicals.

Mondo grass requires regular maintenance. Weeds are the main concern, particularly in sparse areas and during the grow-in. Several herbicides control grassy and sedge type weeds in common mondo grass. Since mondo grass is a lily, some grass killers can be over-sprayed to control invading grasses; Fusilade II works well. Image or Manage controls the sedge-type weeds nutgrass, kylinga and McCoy grass.

Broadleaf weeds are more of a challenge as many of the effective herbicides also injure mondo grass. One way to control broadleaf or any other weed in common mondo grass is the occasional use of Roundup, applied at half of its recommended strength. If you try this, be very careful! Roundup will kill most plants it contacts, however, common mondo grass is rather resistant. Make sure you use the original Roundup formulation, not the newer Roundup Pro.

Do not over-spray onto any other part of the landscape and start out with a small test area. Spot spray as much as possible and do not spray too much in the same area. Wait at least three weeks to access any damage and do not apply Roundup more than once every eight to nine months. Do not use Roundup on dwarf mondo grass varieties they're susceptible to damage from any pesticide. Exercise extreme caution with all chemicals.

An annual application of compost is the best way to fertilize all mondo varieties. Of chemical fertilizers, water-soluble sprays such as Miracle-Gro are best. Granular fertilizers can get stuck in the tufts and burn the leaves.

Common green mondo grass can be occasionally cut with a mower or string trimmer if necessary. Make sure the mower is at the highest setting so that just the tips of leaves are removed. Severe scalping will kill the crowns.

Look for more ground cover options in upcoming articles.

Jay Deputy is an education specialist in landscape horticulture and turf at the University of Hawai'i-Manoa, Department of Tropical Plant and Soil Sciences, and Hawai'i state administrator for the Certified Landscape Technician Program sponsored by the Landscape Industry Council of Hawaii. Send lawn questions to deputy@hawaii.edu.