|'Harper Crewe' is an evergreen perennial with an upright form, to 12 inches high, developed by woody branches. Early spring to early summer flowers are fragrant, double, yellow. Hardy in Zones 5 to 8, this perennial thrives in full sun where soil is poor to moderately fertile and tends toward the alkaline side. Trim after flowering. Grows to 16 inches tall and 12 inches wide.