Hypericum calycinum - Aaron's Beard St. John's Wort

A small semi-evergreen shrub that is covered with bright yellow flowers from mid-summer to mid-fall; chartreuse-bronze new foliage matures to green, then blue-green; perfect for rock gardens or border fronts; best flowering in full sun

Height: 24 inches. Sun: full sun to partial shade. Hardiness zone: 5a.

Ornamental features

St. John's Wort has masses of beautiful yellow buttercup flowers with brick red anthers at the ends of the branches from early summer to mid fall, which are most effective when planted in groupings. The flowers are excellent for cutting. It has bluish-green-variegated forest green foliage which emerges chartreuse in spring. The oval pinnately compound leaves do not develop any appreciable fall color.

Landscape

St. John's Wort is a dense multi-stemmed deciduous shrub with an upright spreading habit of growth. Its relatively fine texture sets it apart from other landscape plants with less refined foliage.

This shrub will require occasional maintenance and upkeep, and should only be pruned after flowering to avoid removing any of the current season's flowers. Deer don't particularly care for this plant and will usually leave it alone in favor of tastier treats. Gardeners should be aware of the following characteristic(s) that may warrant special consideration;

Recommended for: Mass Planting, Hedges/Screening, Rock/Alpine Gardens, General Garden Use, Groundcover, Container Planting.

Planting and growing

St. John's Wort will grow to be about 24 inches tall at maturity, with a spread of 24 inches. When grown in masses or used as a bedding plant, individual plants should be spaced approximately 18 inches apart. It tends to fill out right to the ground and therefore doesn't necessarily require facer plants in front. It grows at a medium rate, and under ideal conditions can be expected to live for approximately 5 years.

This shrub does best in full sun to partial shade. It is very adaptable to both dry and moist growing conditions, but will not tolerate any standing water. It is considered to be drought-tolerant, and thus makes an ideal choice for a low-water garden or xeriscape application. This plant does not require much in the way of fertilizing once established. It is not particular as to soil type or pH. It is highly tolerant of urban pollution and will even thrive in inner city environments. Consider applying a thick mulch around the root zone in winter to protect it in exposed locations or colder microclimates. This species is not originally from North America. It can be propagated by division.

Photo courtesy of NetPS Plant Finder.