A summer-long river of soft lemon-yellow flowers floating above delicate, thread-like green foliage. 'Moonbeam' has earned a devoted following since winning the Perennial Plant of the Year in 1992 — and for good reason. Few plants bloom as continuously or as effortlessly from June through September. The fine-textured foliage gives the whole plant a light, airy quality that softens borders and blends beautifully with bolder companions. Thrives in poor, dry soils where richer plantings would fail.