When you are planning your landscape beds, you need to make a decision on whether you want to use wood mulch or rock mulch. Wood mulch needs ample amounts of nitrogen to decompose in the soil, so it robs your plants of their needed nitrogen. Also it has to be replenished frequently. Rock mulch doesn't decompose so it doesn't use valuable nitrogen from your soil. This allows you to fertilize less frequently. Landscaping with rock mulch is relatively simple and does not take much time at all to create an attractive bed.
Design your landscape bed. Use marking paint to mark the outline of your bed.
Dig a trench 3 inches deep around the entire outline of your landscape bed. The edge of the trench should be vertical on the side facing your lawn, and should slope up at a 45-degree angle toward your planting bed. This will create a barrier for your rock mulch. It will also keep the lawn from growing into the landscape bed.
Lay out your plants in their desired places in the bed. Plant them in the ground and water well to settle the soil.
Spread the rock mulch around your plants to a depth of 2 to 4 inches. Lift any leaves of the plants up and out of the way while spreading the rocks to prevent them from getting crushed under the rocks. Allow the rocks to butt up to the vertical edge of the trench you dug.
Use a leaf blower to remove any fallen leaves or other plant material every few weeks. If this plant material is allowed to decompose in your rock mulch, your rocks will eventually be buried under organic material.