Description

Kalm’s St. Johnswort, Hypericum kalmianum

GALLON POT

Light: Full-sun

Moisture: Wet to moist, well-drained

Soil: Sand, loam

Height: 1–3 feet

Bloom Season: Mid to late summer

Bloom Color: Golden-yellow

Notes: Kalm’s St. Johnswort is a small, semi-evergreen shrub with upright branching stems and an overall mounding form. The linear, dark, blue-green leaves provide a striking background for the clusters of bright yellow flowers that bloom at the tips of the stems. Each cup-shaped flower (1.5-inch in diameter) has 5 petals surrounding a burst of pompom-like stamens. These long-blooming flowers later produce oval brown seed capsules that mature in fall and can persist until the next spring.

Once established, Kalm’s St. Johnswort is a hardy plant—withstanding cold temperatures, temporary flooding or drought, and salt. This small shrub prefers moist, rich, sandy loams but also tolerates rocky soil. It is low-maintenance. Prune after flowering to shape if needed, but never cut the shrub to the ground. Spreads 2–3 feet. Favorite of many bees. Deer resistant.

In landscaping, use Kalm’s St. John’s wort as a foundation or specimen plant, or mass as ground cover on slopes or naturalized areas. Also makes a good low hedge for edging beds and walkways. Can be used in containers. Excellent cut flower.