Perennial gardens are a natural for areas around and under trees, serving to tie the various landscape elements together -- and making mowing easier. Also, lawn grasses often struggle in the shade cast by trees, so it might seem like a great place for some flowers. Some of the most common landscaping questions involve getting plants -- grass or flowers -- to grow under dense trees. Here are some things to consider before digging in.
Shade. Its a fact: Most mature trees cast a lot of shade, and this dense shade limits the types of plants that will thrive there. You may be able to open up the canopy of the tree with some judicious pruning, allowing filtered light to reach the ground. Also, removing some of the lower limbs will let in more light. (Its best to have a professional arborist to tackle major tree pruning.)Competition. Tree roots will compete for water and nutrients with plants nearby, so these plants may need supplemental water and fertilizer.
Though it seems logical to bring in topsoil to create a nice deep planting area, dont do it! Never spread more than an inch or two of topsoil (or dense mulch) under a tree, and never create a raised bed around the trunk. A trees feeder roots are located near the soil surface because they need oxygen, as well as the water and nutrients that filter down. Bury them deeper, and they can suffocate. Also avoid piling soil up against a tree trunk, because this invites disease organisms to attack the buried portion of the trunk.
Whats a gardener to do? Dont expect to grow your most colorful perennial garden under a mature tree. Its not worth the frustration, expense, and risk. Instead, consider introducing shade-loving ground covers and foliage plants with colorful or otherwise interesting foliage, including perhaps some ferns and hostas. You can then incorporate this island into a larger perennial bed, planting the larger, deeper rooted perennials beyond the perimeter of the canopy. Take your cues from nature. If youve ever walked in a mature woodland, youve probably noticed that little grows under the densest trees. Then, as you move toward the edge of the trees canopy, youll notice more and more plant growth as you get further from the tree and into higher and higher sunlight levels.
Smaller, younger trees are more resilient (and cast less shade), so you may be able to establish some perennials near young trees. Dont plant too close, or youll create competition for water and nutrients for the tree, slowing its growth.
Sample Garden Plan for a Shady Garden
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