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Get It Growing News For 04/04/08
By Dan Gill
LSU AgCenter Horticulturist
It’s amazing how many times I’ve gotten questions about growing grass in shady areas. This is a common issue because shade trees in a landscape grow larger over time. Eventually, the shade they create may not allow grass to grow well in the most shaded areas. When dealing with this sort of situation, you have several options.
First – The amount of sunlight reaching the turf can be increased by selectively pruning trees in your landscape. Lower branches and some of the inner branches may be pruned to allow more light to reach the lawn below. Keep in mind, however, raising and thinning the canopy on large trees is best done by a professional arborist who can determine which branches should be removed without affecting the tree adversely Be aware that this is a temporary solution because the trees will continue to grow over the years and shade will once again become a problem.
Second – Choose a grass that will tolerate some shade. St. Augustine grass is considered the most shade-tolerant of the grasses we use for lawns. Among the St. Augustine cultivars available, Palmetto is considered one of the more shade-tolerant. Don’t expect it to grow in heavy shade, however.
Grass growing in shaded areas should be mowed at a slightly higher setting on your lawn mower than normally recommended. This allows the leaf blades to grow longer, providing more surface area to absorb what light is available and to produce food through photosynthesis. St. Augustine can be mowed at a height of 3 inches.
Third – Avoid excessive fertilization because this can increase disease problems. Grass growing in the shade actually requires less fertilizer since it grows less vigorously.
If, after these efforts, you still can’t get grass to grow under your tree, it’s time to accept the situation (as we gardeners often must do) and stop trying to make grass grow where the shade simply won’t allow it. Unless cutting down the tree is an option, your next step is to look at other choices for situations where grass won’t grow.
The easiest solution is to simply mulch the area. Leaves, pine straw or other mulching materials can be applied 4 to 6 inches deep under a tree where grass no longer grows well. This is relatively inexpensive and easy to do and, I think, looks very attractive and natural. After all, in nature trees grow with a layer of decomposing leaves over their roots. Simply add more mulch as time goes by to maintain a 4-inch to 6-inch depth. With the mulch, weeds are rarely an issue and can be controlled easily.
Another option is to plant the area with a shade-loving ground cover or even landscape it with shrubs, annuals and perennials that thrive in shade. For inspiration, take a drive around older neighborhoods with mature trees. You’ll see how areas under large trees can be landscaped beautifully using a variety of ground covers, annuals, perennials and shrubs.
The most important thing to remember when creating landscaped areas under a tree is to respect the root system of the tree itself. Avoid cutting any roots larger than 1 inch in diameter. Use a gardening fork rather than a shovel or spade to turn the soil under the tree because the fork will damage fewer roots. If you need to bring in extra soil to create the bed, use as little as possible – preferably no more than 2 inches to 4 inches. Do not pile several inches of soil up around the base of the trunk because this can lead to decay. If you intend to cover over a large part of the tree’s root system (which extends out well beyond the reach of the branches), don’t apply soil more than 2 inches deep.
A simple alternative to grass is to plant the area entirely with a low-growing ground cover. I think that the best ground covers for covering large areas are monkey grass (Ophiopogon japonicus), creeping lily turf (Liriope spicata) and Asian jasmine (Trachelospermum asiaticum). These ground covers are reliable, easy-to-grow and relatively fast-growing.
Other ground covers suitable for larger areas include English ivy (Hedera helix), Japanese ardisia (Ardisia japonica) and ferns – such as holly fern (Cyrtomium falcatum), leather leaf fern (Rumohra adiantiformis), autumn fern (Dryopteris erythrosora, known for its coppery-red new fronds), sword fern (Nephrolepis cordifolia) and others.
Many plants thrive in partially shaded to shady conditions. Indeed, gardening in a shady area should not be looked at as a challenge or problem but as a chance to grow a wide variety of beautiful plants. I personally enjoy gardening in the shade, particularly in the heat of the summer. Gardens in shady areas are also often easier to maintain because they generally have fewer weed problems.
When the lawn grass finally decides that an area has become too shady for it to grow, don’t fight it. Instead, mulch or choose a ground cover that will thrive in the shade. Or open yourself up to the wonderful possibilities of planting a beautiful and satisfying garden of shade-loving plants.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.
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Contact: Dan Gill at (225) 578-2222 or dgill@agcenter.lsu.edu
Editor: Rick Bogren at (225) 578-2263 or rbogren@agcenter.lsu.edu