Trees don’t grow on the prairie, grass doesn’t grow in the forest. That’s almost true; nature rarely lacks exceptions. Nevertheless we don’t typically see thick, verdant grasses growing in the deep shade of our eastern deciduous forest. Most suburban dwellers have never paused to think about this obvious yet overlooked fact. Our neighborhood trees are often isolated and surrounded by a sea of grass. Suburban trees stand more as individual lawn ornaments, and less like a group of interdependent forest companions. However, with a thorough understanding of the needs of turf and trees, we can improve the conditions for each plant, and subsequently reap the benefits of a lush lawn and a lofty canopy.
The Competitors
Indeed, turf grasses and trees are bitter rivals. Scientific research has shown that fine absorbing tree roots are less abundant when covered with turf grass. Established healthy grasses can outcompete tree roots for water and nutrients. On the other hand, large mature trees often cast a deep shade and deprive grasses of critical sunlight. Some trees, like black walnuts, have devised other strategies to deal ruthlessly with their competition. They produce toxic compounds to poison nearby plants, suppressing their rivals and benefitting themselves.
What’s the Solution? Copy Mother Nature not Your Neighbor
The key to having healthy trees alongside healthy turf is to physically separate the plants. Plant turf grasses only outside of densely shaded areas and remove turf grass adjacent to trees to reduce competition with tree roots.
Commercial mulches can assume the role of the natural layer of nutrient rich duff recycled on the forest floor. Applying an organic mulch, 2 – 4 inches deep and radially from the trunk as far as practical will improve tree root density and overall tree health. By selecting the correct mulch and designing the area carefully, the visual effect will be pleasing and will improve the overall aesthetics of your landscape. Once the neighbors see how it’s done correctly, they can imitate your methods. That is, after all, how we brought about the current dysfunctional trend of seeding grass in deep shade and amongst the protruding surface roots of a large mature tree.
Mulching around your trees is smart. It protects the roots and trunk from severe mechanical damage inflicted by lawn mowers and weed whackers. Separating trees and turf ensures adequate sunlight for your lawn and healthier roots for your trees. Wise landscape design considers the needs of both plants and creates conditions where both trees and turf can flourish.
