Prepping a Shade Perennial Bed Under a Tree
Prepping a shade perennial bed under a tree
We love trees and the shade they provide. But, when it comes to getting plants to grow under mature shade trees, many of us are at a loss. Here we want to discuss how to prepare your under-tree planting bed to grow beautiful perennials and still preserve the health of your valuable tree.
Your first thought may be to vigorously trim that tree in an effort to get sun on the ground beneath it. However, clearing out too much of the tree’s crown can adversely affect the tree’s health. The best way to avoid this is to hire a professional tree service with properly trained arborists and tree workers like Dallas Tree Surgeons. We can help you trim the proper amount to get more light under the tree without causing damage by over-trimming.
Once you have the tree properly trimmed, it’s time to plan and build your planting bed. Larger is better. A nice large bed will give your perennials a chance to spread out, and a broad area of properly applied mulch under your tree is one of the most beneficial practices for your tree’s health. Select a wood chip mulch, not rocks or rubber. Such inorganic mulches do not improve soil conditions and keep the root zone too hot. Also, when applying your organic mulch, keep it away from the tree’s stem and root flare. Covering these areas may lead to bacterial or fungal infections and insect infestations. It may be tempting to raise the grade and build a deep planting bed under your tree. DON’T! Your tree’s roots need access to oxygen to use the carbohydrates generated by photosynthesis. If roots are cut off from oxygen long enough, they will die. Your bed, including soil and mulch, should not add more than four inches to the existing grade under your tree. So, a large, shallow bed is much better than a small, deep one.
If you have an existing lawn or weeds under your tree, place newspaper 2 to 3 sheets thick on the lawn under your new garden soil and mulch. This will help smother the grass and weeds without smothering the tree’s roots because newspaper decomposes quickly. Landscape fabric or plastic are not good alternatives because they will create a barrier between your tree’s roots and the oxygen and water they need.
Now that you have your bed’s soil and mulch installed, it’s time to bring on the plants! We will explore shade perennials that grow well in North Texas in future blog posts. When planting under a tree, it’s best to plant smaller nursery stock, not larger than 1-gallon pots. This will reduce root competition between the tree and your new perennials and minimize any disturbance to your tree’s precious roots.
It may seem like a lot of work, but properly preparing your under-tree perennial bed will provide you with a cool, beautiful spot to enjoy nature for years to come. Don’t forget the bench!