When landscaping plants in areas with full sun, it's important to ensure that the soil can maintain adequate moisture for the plants' needs, particularly if you are not installing a sprinkler or irrigation system in your landscape. You can still grow plants that require a lot of water by amending the soil and using organic mulch at the planting site.
Choose perennial landscaping plants that grow best in full sun with a long season of bloom. Some examples are roses, peonies, poppies, purple coneflower, hollyhocks, Russian sage, black-eyed-Susan, hardy hibiscus, yarrow and delphinium.
Add organic soil amendments to the planting bed to hold moisture and help keep the soil from drying out. Add 2-3 inches of peat moss and 1-2 inches of compost to the surface of the soil. Dig it by turning over the top 6-12 inches with a garden shovel. A thin layer of perlite can also be added before turning the soil under. Perlite is volcanic rock that is exploded like popcorn and holds many times its weight in moisture. Perlite is available at garden centers.
Put down a 4-6 inch layer of organic mulch to help keep the soil evenly moist, reduce competition from weeds and help to enrich the soil as it decomposes. Organic mulch material that gives a polished look to your landscape includes shredded pine bark, buckwheat hulls, cocoa hulls or redwood chips.