We have recently discussed the merits of different traditional varieties of lawn grass seed (January Yard Talk) and the use of native grass (May Yard Talk). In this issue, we would like to address one of the hardest uses of grass in the home’s landscape, growing grass in heavy shade.
To begin with, grass really does not want to grow in heavy shade. Just take a walk in the woods and observe how much grass you see growing. Sure, some grasses will grow in shade but, it is not natural for it to grow there. Fine fescue tolerate partial shade but, do not like this condition. Among the more commonly used varieties of the fescue are: Jamestown, Banner, Barfalla, Checker, Highlight, Koket, Shadow, Dawson, Ensylva, Fortress, Pennlawn, Ruby, and Aurora. Some perennial ryegrasses offer intermediate shade tolerance. Ryegrass varieties for shade include: Birdie II, Citation II, Fiesta II, Manhatten II, Palmer, and Regal. Poa trivialis L or rough blue grass can also be used in shaded areas.
The best solution for the homeowner who wants a traditional well-groomed suburban lawn is to cut down all his trees and grind them up for use as mulch in his flower beds. Of course, if you live in an urban setting you will probably have to do this to your neighbors trees as well. While this will greatly insure that you have a beautiful lawn, it probably is not too practical. Some compromises will need to be made, particularly if you want to stay out of jail. Ideal growing conditions for lawns include sun, fertile, well-drained soil, and enough rain for the lawn to grow.
The first and most important thing we need to do is to make sure the lawn is receiving enough sunlight. The grass may not get enough sun to manufacture food efficiently through photosynthesis to support the growing grass plant. Also, if a tree is casting shade, it may also be competing with the lawn for available water and nutrients, and may even block water from getting to the lawn during light rains. You need to evaluate the trees in your yard. If the trees are old, damaged, or of an undesirable species you may wish to have them removed. Poplar and Cottonwood trees are short lived and brittle, while Walnut and Cherry are messy and their roots and leaves leach out chemicals that can inhibit plant growth. Some varieties of Maples and Ashes have root systems that are very close to the soil’s surface, even growing on top of the soil. If you decide that the trees are worth maintaining, you then should have them pruned and thinned by a trained professional.
This does not solve your problem if the trees shading your lawn are on your neighbors’ property. Hopefully, he takes pride in his landscape areas also and keeps his trees pruned. If not, you can always offer to pay to have his trees trimmed. Many large cities also have ordinances that might offer some legal relief.
Often, shaded areas under trees are also very infertile. Unfortunately, most homeowners and even lawn services treat these areas like the rest of the lawn. You want to treat these areas with a low nitrogen fertilizer or, at least, a balanced one such as 13-13-13. We like to reduce the amount of the application and increase it’s frequency. We reduce the application to half strength and instead of applying 6 times we use 12 applications a year. Remember, most of your fertilizer is going to be absorbed by the trees.
The soil in shaded areas quickly becomes compacted, particularly if it is along a walk or drive. While we generally only aerate a healthy lawn every 3-5 years, a heavy shaded area should be done yearly. This will improve the drainage and increase air penetration. We always follow aerating with a top dressing of a good quality grass seed. This is also a good time to apply a topdressing of organic matter such as mushroom compost although, any compost will help. In a heavy clay soil, you may wish to make two compost applications, you are trying to increase the organic content of the soil.
Areas under trees need much more water than other areas of the lawn. Like fertilizer, most of the water is going to be taken up by the surrounding trees. This is one area where an underground sprinkler system more than pays for itself. Next to sunlight, nothing is more important than the timely application of water. Poa trivialis L, for example will grow very well in heavy shade with lots of watering, cut back the water and it quickly dies out. We never use Poa trivialis L unless the lawn has an irrigation system. To grow grass in the shade, you must make the commitment to watering regularly, this means even when you are out of town. Unlike grass growing in sunny locations, grass in shade does not go dormant during dry spells, it dies!
For those of you with children, if you want good grass, provide them with another play area, take them to the park, or have them play at the neighbors. If you like picnicking in the shade, buy an umbrella. Grass in shaded areas just will not tolerate heavy traffic nor will it recover if subject to it. This includes the wanderings of the family dog.
This probably sounds like a lot of work and it is. It can be very expensive and require sacrifices. Most of all, it takes a commitment on your part to keep doing the things that are required when they are required. If you quit for any reason, the grass is gone and you have to start over. It is just that simple.
