DESCRIPTION: This large group consists of about 370 perennials and evergreen and deciduous trees and shrubs that grow throughout the temperate regions of the world. These plants are great for the rock garden, herbaceous border and shrubbery. The shrubby kinds are especially pretty as they produce a profusion of bright or golden yellow flowers in the summer and autumn. The blossoms have five petals and numerous, prominent stamens. E. calycinum (Aaronsbeard; St. John's Wort) is a dwarf, evergreen shrub with large leaves and clear yellow flowers. It is great as a ground cover in dry, shady sites, but if left alone can become a pesky weed. E. forrestii is a hardy, deciduous shrub that usually grows up to 3 or 4 feet high. The leaves turn pretty colors in the autumn and remain on the plant into early winter. Throughout the summer and autumn, this shrub in clothed in saucer-shaped, golden yellow flowers that are 2 to 2½ inches wide. H. moserianum (Goldflower) is a dwarf to small-sized, deciduous shrub that normally doesn’t grow over 20 inches high making it a great groundcover. The flowers are produced from mid-summer to mid-fall. Their reddish anthers contrast nicely with the golden petals. A variety of H. moserianum, called Tricolor, has leaves variegated with green, pink and white. This dwarf to small, deciduous shrub flourishes in a sheltered location or in a greenhouse. H. olympicum var. Citrinum is a dwarf shrub with terminal clusters of very light yellow (almost whitish) flowers about 1¼ inches across.
POTTING: These plants will flourish in almost any well-drained soil in a sunny or partially shaded location. Most of these plants require little or no pruning except for H. calycinum, which should be cut to ground level every other spring. Decayed manure or compost can be placed above the roots every two or three years. H. inodorum and H. calycium are very susceptible to rust.
PROPAGATION: Cuttings or seeds of the shrubby kinds may be used. Soft shoots, taken in June or July and inserted in sandy soil in a closed frame, will form roots quickly. Seeds aren't used often. The herbaceous kinds and H. calycinum can be increased by division. Some of the herbaceous kinds spread so quickly that if they aren't kept within bounds, will become an aggravation.
VARIETIES: H. androsaemum (Tutsan); H. olympicum (Olympic St. John's Wort) & var. Citrinum; H. calycinum (AaronsBeard; St. John's Wort); H. coris; H. cyathiflorum & var. Gold Cup; H. forrestii; H. inodorum; H. kouytchense; H. moserianum (Goldflower) & var. Tricolor; H. 'Rowallane'; H. 'Hidcote'; H. aegypticum; H. balearicum; H. quadrangulum; H. Buckleii; H. polyphyllum; H. empetrifolium. H. frondosum (aureum); H. densiflorum; H. Kalmianum; H. galioides; H. prolificum; H. Hookerianum; H. patulum.H. Ascyron; H. japonicum; H. perforatum (this & possibly others are regarded a being poisonous to stock); H. elegans; H. humifusum; H. linarifolium.