Beginner Gardening: Planting within a Retainer Wall, 1 by Kate29161

Kate29161 wrote:
Hello,

We just finished a 2 block retainer walls that are 130 ft long and 6 ft high. This walls are visible from the main road which is 800 ft way and I would like to do something that will be visible from the main road as well as improving the yard. This lower section in between the walls has 1 ft of good black dirt. I thought I might plant Hisbiscus's in this area because the flowers are big. My concern is how will this plant survive the heat from the upper wall if I am not able to water it daily? Are there any other large or showy plants that I could use for this section? I prefer not to use shrubs. I plan to plant informal cottage type flowers with a variety of color in the upper section.