How to plant around a tree

Credit: Courtesy Scott McLeod

Q: Can I install a raised flowerbed around an existing tree without damaging it? 

Installing a new raised flowerbed can add significant curb appeal to any home by allowing the plants to be easily viewed from the street. In many landscapes, an existing tree has been planted at an elevation much lower than what is required for a raised flowerbed. At first glance, the homeowner has only two choices: design the flowerbed at the level of the tree or dig up the tree and replant it at a higher elevation. Both options are usually less than ideal. The good news is there is a third option that is often overlooked. Here is what I recommend:

Shape the flowerbed around the tree using a halfmoon blade and remove all turf and related roots in a way that won’t disturb the roots of the tree.

Add Sea Soil or a well-composted organic garden-blend soil to the newly formed flower­bed area. At this stage, don’t be afraid to place the soil right up against the tree trunk until you have reached the proper elevation.

Carefully begin to dig out a circle around the tree trunk and remove all the soil to adequately expose the root flare of the tree (where the tree trunk meets the soil) without damaging the bark. This is critically important so that the tree maintains a healthy root and stem structure and the root flare won’t rot over time. The diameter of the circle depends on the size of the tree and the look of the surrounding area.

Choose a selection of rocks that are in proportion to the size of the tree and surrounding area and that match the colour scheme of your yard. In this case, the rocks are approximately 30 cm (1 ft.) wide by 90 cm (3 ft.) tall or more, depending on the depth of the soil from the top of the new bed down to the root flare. You will need enough rocks to cover the circumference of the circle. Next, place the rocks in such a way that they act as a retaining wall keeping the soil in position and away from the tree trunk. Finally, after the large rocks are installed, fill the hole roughly 15 cm (6 in.) deep (depending on the total depth of the hole) with a selection of river rock, making sure that the rock is kept away from the trunk of the tree.