A great plant for that spot is sedum. Sedum, or stonecrop, thrives in Colorado's poor soil and dry climate.
Sedums are usually succulents with green, gray or red leaves.
Sedum flowers are small, star-shaped and usually borne in clusters. They range in color from white and yellow to pink and purple. The easy cultivation of sedum is a Gardener's dream. Most root easily from stem cuttings. They thrive in alkaline soil and full sun.