Out of some 500 species, only a dozen or so are widely cultivated. Of these, annuals are grown mainly for cut flowers; perennial kinds are valued for soft, silvery foliage. All are relatively easy to grow. For best performance, add lime to acid soils. Sow seeds of annuals or set out plants of perennial kinds in spring or fall. (In desert regions, plant all in autumn for winter and spring bloom.)Centaurea macrocephala
From the Caucasus. Attractive, coarse-foliaged, leafy plant 3–4 ft. tall, 2 ft.wide. Blooms in summer, bearing 2-in. clusters of yellow flowers tightly wrapped at the base with overlapping, shiny, papery brown bracts. Flower heads resemble thistles. Use in fresh or dried arrangements.
To 8– 15 ft. tall and wide, with arching branches. Lobed, maplelike dark green leaves to 2&ndash
Native to eastern North America. To 1–1 1/2ft. tall, about 3 ft.wide. Most useful for shaded sit...
To 6–8 in. high and 8 in. wide, with smooth, wavy-edged leaves. Purple, pansylike, slender-spurr...