Verbena. Verbena Is The Ideal Plant To Cascade Over Retaining Walls Containers Baskets And Window BoxesAs Long As Its Soil Is Well Drained Verbena Will Reward Gardeners With Countless Clusters Blooms All Season LongVerbena Is Also Drought Tolerant Making It A Great Choice For Rock Gardens And For Planting In Cracks Between Stones. www.bhg.com