Q. I hope you can give me advice on my lawn problem. I seem to be losing more lawn every year, even though I fertilize and treat it. Last season, the professional lawn service gave up and refunded my money. I have rocky soil with lots of shade, but even where there is sun, the grass seems to grow and die off. I even have put in shrubs with soil and they die in about a year. Now I am looking at almost all mud with erosion. What should I do? Help! -- Rich R., Randolph
A. Your first step should be a soil test. This will allow you to determine the pH and nutrient levels of your soil. You may need to amend your soil with organic matter to enable plants to grow properly. Contact your local Cooperative Extension office to find out about soil test kits. Visit njaes.rutgers.edu/county for a listing of Cooperative Extension contacts throughout the state.
Partially shaded areas
You may need to temporarily stabilize steep banks in partially shady areas with a quick-growing perennial ryegrass and a mixture of fine fescues. The ryegrass will germinate quickly to stabilize soil, but eventually fade in the shadier areas. The slower-growing fine fescues will become established in partially shady areas and form fibrous roots to help hold in soils. Use a thin layer of clean straw, compost or strips of burlap secured with landscape pins to stabilize sloped areas until grass emerges. You can get rolls of burlap at local garden stores.
Densely shaded areas
Most cool-season grasses grow best in full sun to partial shade. The grasses that perform the best in partial shade are fine fescues. Of all the fine fescues, hard fescues and creeping red fescues will grow best in low-input landscapes with marginal soils. Very few grasses will thrive in full shade and provide a substantial cover that will stop erosion.
In your circumstance, you need to stabilize soil quickly to prevent further erosion. Without looking at your site, it is difficult for me to determine what will work best. However, a number of commercial landscape fabrics are available that could accomplish this task. I would recommend that you look for a landscaper with experience creating terraces and working on slopes with shade-loving plants.
You may need to use landscape fabrics and barriers to curtail erosion and prevent soil loss. I have stabilized soil successfully using burlap and landscape pins available at most garden centers. Burlap comes in 25-foot to 100-foot rolls and can be used in strips on the worst part of slopes to prevent erosion.
Look for groundcovers that will thrive in shade and provide needed cover to prevent erosion. Two common evergreen choices are Pachysandra terminalis, which will grow in dense shade, and vinca minor, or periwinkle, which will grow in partial shade and provide blue to purplish flowers. Liriope muscari ('Big Blue' lilyturf) or Liriope spicata (creeping lilyturf) also can be used in dense shade between other plants and can tolerate clay or sandy soils. A nonevergreen option is Convallaria majalis (lily of the valley), which performs well in dry, shady conditions.
If you have steep slopes, then you may need to stabilize the slope by creating terraces, or steps. This is best done by a landscaper who has experience creating terraces. Ask for references and visit the contractor's previously landscaped sites, if possible. Terracing slows down the speed of water flow after rains, reducing potential erosion. Terracing also allows plants on terraced steps to absorb needed water. Flat areas on the stepped terrace make it easier for gardeners to manage sloped landscapes.
Utilizing stone or blocks at strategic points along the slope may also help prevent soil loss and provide an opportunity for plants to become established. These structures should fit into the overall design of the surrounding landscape (consider size, shape, color and texture).
In areas where there is very little soil left, you may need to add quality topsoil or amend the native soil with well-rotted compost or peat moss. Mix the amendments into the soil and adjust the pH to match the needs of the plants. Mix the compost or peat moss into the top 8 inches to 10 inches of soil with a roto-tiller or gardening spade. After seeding or establishing groundcovers or other plants, be sure to stabilize the soil around plants with a fabric to prevent further soil loss.
Here are some groundcover choices for shady or partially shaded areas:
Bunchberry (Cornus canadensis): Thrives in moderate to dense shade and produces white flowers.
Carpet bugle (Ajuga reptans): Thrives in shade but may invade lawns.
Dwarf lily turf, mondo grass (Ophiopogon japonicus): Thrives in partial to dense shade and produces white to blue flowers.
Lady's mantle (Alchemilla mollis): Part to moderate shade, green flowers.
Pachysandra, Japanese spurge (Pachysandra terminalis): Evergreen that thrives in light to dense shade with white flowers.
Phlox, creeping phlox (Phlox stolonifera): Thrives in light to moderate shade and produces blue flowers.
Wild ginger (asarum): Shade lover, very aromatic, needs moist soils.