A flower bed with a defined border turns an ordinary tree into a major focal point in your yard. Natural stones, such as river rocks, work well for flower bed borders because they are organic, but balance the soft plant features. If the tree is on a slope, then you must build up the border in several levels on the bottom side, creating a sort of half retaining wall, so the soil in the flower bed doesn't erode in heavy rainfall.
Lay a garden hose on the slope around the tree to form the outline for the border. Transfer the design to the ground with line-marking spray paint.
Measure the dimensions of the stones for the border; use the average measurement to build the border. Choose stones that are roughly the same size and not taller than 4 inches.
Dig a trench about 2 inches wider than the widest stone and about 3 inches deep, plus half the height of the stones. Use a half-moon edger to cut straight sides in the trench; use a spade to dig out the soil.
Add 3 inches of crushed rock to the trench and pack it tight with the blunt end of a digging bar.
Add 1 inch of masonry sand to the trench and spread it out evenly. The sand will not be level because you are installing the border on a slope.
Fill the trench with the landscaping stones, with half the height of the stones below soil grade. The top of the slope only requires one course of stones to complete the border.
Stack a second level of stones directly on top of the first level; stagger the joints for stability and set the stones in slightly so erosion doesn't push the stones over. Begin adding the stones at the bottom of the slope and work to the top of the slope, stopping when the second level of stones is even with the first level of stones at the top of the slope.
Fill in the space within the stones with topsoil up to the edge of the second course of stones. Do not push the soil directly against the tree trunk; leave about 4 to 6 inches from the trunk free of soil to avoid rot and infestation.
Add a third level of stones on top of the second level of stones, working from the bottom of the slope. Stop adding stones when the third level of stones rests at the same level as the stone at the top of the slope. Fill in the space with topsoil up to the top of the stones.
Continue adding courses of stones, working from the bottom of the slope up to the top of the slope. Fill the space with topsoil up to the top of the stones after completing each course. When finished, the stones at the bottom of the slope should be level with the stones at the top of the slope, creating a sort of half retaining wall at the bottom of the slope. Do not add soil after adding the final course of stones.
Plant your choice of flowers in the top soil around the tree, planting to the same depth as the original planting container. Add about 3 inches of mulch around the flowers, leaving 1 to 2 inches from the top of the mulch to the top of the stones.
Things You Will Need
- Garden hose
- Line-marking spray paint
- Measuring tape
- Half-moon edger
- Crushed rock
- Digging bar
- Coarse sand
- If the tree has exposed roots, which indicates poor drainage in the soil, then you must mix the topsoil with equal parts sand and apply only about 1 inch at a time every 10 days to slowly acclimate the tree to the new soil.
- This project works best on slight slopes where no more than three or four courses of stone are needed to build the wall. Do not attempt this project on a severe slope because you risk smothering the tree roots.
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