Sunny blossoms and bright berries make St. John’s wort shine among other shrubs and perennials.
You may be familiar with the name, but you’ll likely be surprised how many forms Hypericum can take. From the remedy known as St. John’s wort to the floral arrangers’ favorite with bright berries, there’s a Hypericum for nearly any garden.
Those familiar with herbal medications will recognize St. John’s wort (Hypericum perforatum) as a remedy for depression and anxiety. Centuries ago, these ailments were considered the work of demons or the Devil, and garlands of St. John’s wort were hung over religious icons during summer festivals to ward off evil. Hence hyper meaning above, and eikona, a picture.
In the landscape, St. John’s wort has a similar beneficial impact with its cheery yellow blossoms that give way to woody seed capsules or bright berries, often used in floral arrangements. The long-blooming, bright yellow flowers range from about ½ inch across (dense hypericum) to 2–4 inches in diameter (Aaron’s beard, H. calycinum), always centered with a conspicuous cluster of stamens. Happily, these shrubs and their berries are deer-resistant.
St. John’s wort or Hypericum species belong to the family Hypericaceae (a subfamily of the Clusiaceae), which includes almost 500 species. They hail from most parts of the world, including mountainous areas, woodlands, and scrubby regions with poor sandy soil. Some, such as dense hypericum
(H. densiflorum) are native to North America. The genus includes shrubby species such as golden St. John’s wort (H. frondosum) and subshrubs such as partly woody tutsan (H. androsaemum). Others are herbaceous perennials such as common St. John’s wort (H. perforatum), which is considered invasive; some trailing (H. cerastoides); or annuals such as bog hypericum or tinker’s penny (H. anagalloides). Usually bluish-green, the foliage may be deciduous or evergreen. Some species display good fall color.
St. John’s worts are included in shrub collections for their yellow flowers and long bloom time. One of the showiest is hybrid ‘Hidcote’ with clusters of fragrant, yellow flowers from early summer until fall. Irish ‘Rowallane’ is another winner with semievergreen foliage and trios of large, dark golden blooms. Evergreen, with 2-inch-long bluish-green leaves, Kalm St. John’s wort (H. kalmianum) is excellent for shrub borders, low hedges, or native plant gardens. Its clusters of gold flowers are followed by attractive brown oval fruits. The hardier cultivar ‘Ames’ and free-blooming H. x ‘Deppe’ (marketed as Sunny Boulevard) blooms all summer, is more compact, and is heat-tolerant. Native, semievergreen golden St. John’s wort displays showy flowers and fruits. In cold climates, the foliage drops in fall. ‘Sunburst’ is more compact with slightly larger blossoms; mature plants display exfoliating bark in winter. Tutsan is known for its groups of green berries that ripen to red then black. The Hypearls and Mystical series have berries in assorted colors.
In light shade certain St. John’s worts, particularly Aaron’s beard, are effective as groundcovers. Somewhat assertive, they produce a carpet of large, sunny yellow flowers from midsummer to fall. ‘Brigadoon’ has bright yellow leaves. The young foliage of Golden Rule is orange, becoming yellow. Don’t pass up this genus of colorful plants for your garden. Perhaps not as well-known as some genera, your St. John’s worts likely will be conversation starters wherever you grow them.
Shrubby St. John’s wort (Hypericum prolificum) Tutsan St. John’s wort (Hypericum androsaemum)