|This is a hardy, upright, clumping perennial, to 28" tall and 18" wide. Leaves are lanceolate to oblong, wrinkled, pubescent, medium green, to 3" long. Widely grown for its tall, dense, indigo blue, spiked summer flowers with bracts of similar color. Outstanding for mass plantings, borders, or containers. Thrives in full sun. Heat and drought tolerant. S. x sylvestris is a hybrid of S. nemorosa and S. pratensis.