Ornamental trees are beautiful additions to your landscape. Perhaps you're considering tree islands to lessen the amount of lawn maintenance, or to hide or show off tree roots. Before heading to the nursery for a number of ornamental perennials or annuals, keep in mind that the tree root and drip line environment only allows a select number of plants to thrive.
Test the acidity of the soil underneath the tree with a pH testing kit. If your tree is healthy and thrives, you do not want to upset the pH balance of its soil by introducing plants that require a more alkaline or acidic growing environment. As a general rule of thumb, if your soil pH level tests at 7.0 or below, it is acidic; a pH above 7.0 makes it alkaline.
Purchase ornamental or groundcover plants that thrive in the tree's soil. For acidic soil, consider planting heather, wintergreen, rhododendron or azaleas. If the pH test shows that the soil tends to be alkaline, opt for ladies' fingers, crown vetch, foxtail lilies or pincushion flowers. Does your tree have a dense canopy? Add the ability to thrive in shade or partial sun as one of the prerequisites when choosing your plants.
Apply the measuring tape to the tree trunk. Determine a 1-foot radius all the way around the tree. Do not plant anything within this perimeter.
Dig planting holes with a small shovel. Proceed slowly and be prepared to fill in the hole if you encounter tree roots. The majority of tree roots does not reach deep down into the soil but instead remain as close as 12 inches within the soil's surface. Do not cut roots with a two-inch diameter or bigger, and do not try to move them out of the way.
Remove a plant from its pot. Gently loosen up the root-ball before placing it into the prepared hole. Replace the soil in the hole and gently press down. Move on to the next hole and repeat the process with each plant.
Mulch the area around the tree and flowers. (Do not allow mulch too close to tree trunk.) The mulch helps with moisture retention and reduces the appearance of unwanted weeds.
Water the planting area well. Depending on water restrictions and rainfall in your area, water as often as needed to help the plants establish themselves.