Most trees are deep rooted and suitable for under-planting with shade loving perennials. Some trees may not be a good option as an overhead companion for shade-loving plants.
- Maples, willows and poplars/cottonwoods have dense, shallow roots which can be too difficult to dig through. Planting under these trees may require constructing a raised bed around the base of the trees with about 8 inches of new soil placed over weed barrier.
- Walnuts (all types) release chemicals into the soil that act as natural herbicides, thus eliminating competition from plants growing under and around them. Don’t plant under or around them.
- Large conifers (evergreen trees) are also tough as the shade they cast is very deep and the overhead branches absorbs most if not all the rain and snow that fall on them, creating an extremely dry soil. When planting under big conifers it’s essential that irrigation be used to provide sufficient water for your shade garden plants.
Shaded growing conditions found under these trees and shrubs can be particularly challenging because of root competition and overhead branches that absorb much of the precipitation. This, in turn, creates dry, nutrient-deficient soil conditions that require dry shade-loving plants.
Remember these tips for planting beneath challenging trees and shrubs:
- It is extremely important when planting under trees and large shrubs, that the planting holes be nice and wide and free of fine fibrous feeder roots. Removing feeder roots from the planting hole is essential so that new transplants can establish their roots with minimal competition
- Also make the effort to enrich the soil adequately with ample amounts of Yum Yum Mix and a good quality compost mixture. This will also help the new plants to get off to a great start by providing the nutrients necessary for establishing strong roots.
- Keep your new transplants well-watered for the first couple of growing seasons to get the perennials well established before the tree/shrub roots move back in.
- It's very important to fertilize shade gardens regularly in the fall to provide the perennials with adequate nutrients.