All plants need water to survive. However, like plants that require more water, there are plants that grow in lack of water. They are the best drought tolerant plants and can live without water for a long time.
Purple Flowering Groundcover - Campanula Portenschlagiana - a plant that grows in less-than-ideal conditions and has long-lasting foliage. Plant care info is on the post - via Northern Shade - Gardening Daily
Lavender: Create a thick hedge by making your ridge 24 inches wide and set lavender plants in two rows 12 inches apart. Instead of planting in parallel rows, stagger plants so plants of one row are halfway between plants of the other row. Lavender needs g