There are many selections of Moss Phlox, all of them forming a low mound or cushion of dark green needle-like leaves, throughout the spring and summer months the evergreen cushions are drenched with cute star-shaped Lilac flowers. this beautiful perennial is often used for flower borders, rockeries, for edging, or in mixed containers.. this evergreen perennial grows best in well-drained, fertile soil. Good drainage is paramount when growing Phlox. drought tolerant, once established.