This month’s gardening article deals with a common challenge I run across with landscaping clients… a desire for thick, lush grass under mature trees like it grows in the rest of the lawn. Though hot summer weather makes shade a premium commodity in a yard, too much can prove deadly to grass species often found in lawn turf. It boils down to this… grass needs full sun to thrive. Yes, it can be coaxed to “eek” by in partial sunny areas, such as those found under trees spaced widely enough apart to allow sun most of the day. In fact, grass often appears healthier and stays greener longer when it gets “some” reprieve from the scalding sunlight for part of the day. However, the conditions under a mature shade tree are not conducive to growing lawn, especially if you want it thick and lush all the way up against the trunk.
The need for sunlight helps people understand the misdirection of wanting lawn under a mature maple, oak, cherry, plum or apple tree. It just isn’t going to look like lawn that gets full sun. Grass under a tree will be thinner, shallow-rooted, weaker due to competing with the tree roots for moisture and nutrients, and it’s often patchy the closer it is to the trunk where sunlight rarely touches at all.
The “different” conditions found beneath trees make it a poor choice for growing lawn. It makes sense to compromise… a mulched bed 6-8 ft diameter around the base of each mature tree. Each mature tree should have a mulched bed covering a large portion of its drip-line (the imaginary perimeter directly below the canopy of branches that contain the majority of tree roots). Not only does this technique minimize competition between thousands of grass plants and the root systems of your trees, it also provides an insulating layer of mulch that maintains moisture for your tree, moderates both hot summer and cold winter temperatures, blocks weeds, provides delineation between lawn and the root-zone of trees… a smooth circle that’s easier to mow, without having to resort to weed-eating that can damage tree bark.
A completely independent benefit is that these mulched beds can be filled with a few shade plants that WILL thrive under trees and give you color, contrast and texture a lawn simply can’t provide. There is also an advantage of covering the knobby surface-roots that play havoc on your lawn mower when you try to mow under the tree. Mulched beds are a tidy solution to a number of problems of lawns growing right up to the base of tree trunks. Even if you don’t want grass under your trees, perhaps the most valuable thing you can do for your trees is mulch a bed around their base. They will grow more each year, suffer less from temperature extremes, benefit directly from the fertilizer you put around their root zone instead of competing with grass, and be much easier to mow around. I encourage you to consider beds around all your trees.
Email your gardening questions to email@example.com. Written, edited and distributed by Di Braun for free personal use by those who enjoy gardening. Please contact the writer for details on redistribution through commercial entities. Click on ventwing.com/gardening-in-anchorage/di-braun for an archive of landscape newsletters and articles.