Verbena Rigida, or slender vervain, is a low-growing perennial species that produces an abundance of punchy purple flowers from summer and into autumn. Its lax growing habit makes Verbena rigida fantastic for planting in great swathes and softening the edges of borders. It will also self-seed, and makes a great addition to sunny gravel gardens and wildlife gardens. For best results grow Verbena rigida in moist, well-drained soil. It’s not fully hardy, so grow it in well-drained soil and avoid excessive winter wet to help ensure it returns each year.