Shade is, quite possibly, the most gradual, and therefore most unnoticable, problem that affects lawns. We have many lawns, which we’ve been servicing for years, that are experiencing a decline in turf vigor because of the increased amount of shade being cast both by trees in the landscape and those around the perimeter of the property.
Trees and a healthy stand of turf are often incompatible. In the battle between trees and turf for nutrients, light, air, and water, the trees always “come out on top.” Sure, there are more “shade tolerant” grass types, but even these can’t tolerate the deep shade that large trees cast.
Here are the problems that trees create:
Shade. A lack of light does not allow for adequate photosynthesis. This creates a weak grass plant
Excessive moisture. The lack of light, and heat, creates a cooler environment that naturally retains more moisture. This is true even with the tree taking more moisture. This is especially true when irrigation systems are used without considering the extra moisture that is already in shaded areas.
Soil compaction. This is a byproduct of excessive moisture and weak turf. When soil is constantly too wet from excessive moisture, it doesn’t support a healthy turf root system. Without a healthy root system to keep it loose, the soil will compact to the point that nothing but moss will grow there.
Moss. Since moss has no root system and will tolerate shade much better than will turfgrass, it will thrive in the shade. As pretty as moss can be, it’s also a hazard for foot traffic, since it pulls up so easily and can create a slippery surface.
What can we do to control shade?
Here are some steps that you can take to control the growth of shade:
Keep trees properly pruned. This is probably the easiest practice to have performed on a regular basis. Raise the trees by pruning the lower branches of large trees up to about 25 feet.
Keep perimeter trees from encroaching over the lawn. This is a major problem with many landscapes. Deciduous trees (those that lose their leaves in the fall) are “phototropic”. This means that they’ll grow toward the light. When you clear trees to create a manicured landscape without planning for the fact that the surrounding towering trees will grow toward the open space that you’ve created, you’re setting yourself up for shade problems down the road.
Remove trees that the outgrown their location. This is often advisable with trees that have been planted too close to the house, driveway, walkway, etc.
Plan for specimen trees to have a large ring of mulch beneath them. If you want to have beautiful, large tree be a centerpiece of your manicured property, plan on not growing dense turf beneath it. A mulch bed, or some other non-turf landscape material, under the tree and out to the “drip edge” will provide for a more attractive landscape than trying to grow grass under a landscape giant.
Install the right tree for the desired result. Smaller, ornamental trees are more compatible with a manicured lawn than are maple trees. Maple trees are notoriously shallow rooted. You’ll often find a lot of surface roots that will interrupt a lawn underneath and create unstable footing. Oak trees seem to be more “lawn friendly” but still must be pruned up to keep enough daylight in.
Surrender some lawn to a large tree. If you have a large tree that you don’t want to prune, remove, or otherwise alter, then stop trying to grow grass beneath it. Sometimes it’s better to put mulch, or some other type of shade-tolerant ground cover, than trying to sustain a thick lawn.
Use shade tolerant grass types. The fine fescues are regarded as more shade tolerant than are bluegrasses or ryegrass. Even then, they’ll need some light to establish and thrive. Don’t think that you can grow shade tolerant grass in an area more suitable for mushrooms. It won’t work.
The bottom line is to accept that shade will compromise a lawn if trees and shrubs are allowed to grow unchecked. Plan on a maintenance program to keep trees pruned up and large shrubs controlled to a desirable size.