A sun-loving, low-growing, 2- to 3-foot-high, native shrub found in moist, low areas in the upper Great Lakes. The long-blooming, bright yellow summer flowers have showy, pompom-like stamens. Best used in mass for full effect.
This species is native to the Chicago Region according to Swink and Wilhelm's Plants of the Chicago Region, with updates made according to current research.
This plant has some cultivated varieties. Go to list of cultivars.
All common names:
Tree or Plant Type:
- Chicago area,
- North America
- Small shrub (3-5 feet),
- Low-growing shrub (under 3 feet)
- Full sun (6 hrs direct light daily)
- Zone 4,
- Zone 5 (Chicago),
- Zone 6,
- Zone 7
- Moist, well-drained soil
- Occasional flooding,
- Clay soil
Seasons of Interest:
- early summer,
- late summer,
- early fall
Flower Color & Fragrance:
Shape or Form:
Tree & Plant Care
Best in full sun in moist to well drained soils.
Flowers on new wood, prune in spring.
Disease, pests, and problems
Disease, pest, and problem resistance
Tolerant of salt, drought and soil compaction.
Native geographic location and habitat
Found in moist soils near ponds and dune areas around the Upper Great Lakes region.
Attracts birds, pollinators, or wildlife
Birds and butterflies are attracted to flowers and seeds.
Bark color and texture
Twigs are slender, reddish-brown, older stems have exfoliating bark exposing a bronzy colored inner bark.
Leaf or needle arrangement, size, shape, and texture
Alternate, 1/2 inch wide linear to oblong leaves up to 5 inches long.
Medium bluish-green upper leaf with small glandular dots beneath.
Flower arrangement, shape, and size
Bright yellow, 5-petaled flowers with pompom-like stamens. Long blooming.
Fruit, cone, nut, and seed descriptions
Brown capsules about 1/4-inch long, persist into winter.
Cultivars and and their differences
Ames St John Wort (Hypericum kalmianum 'Ames'): A small, 2 to 2 1/2 feet high and wide, rounded shrub from Iowa State introduction program, 1-inch wide golden yellow flowers in summer, extremely hardy.
Gemo St. Johns Wort (Hypericum kalmianum 'Gemo'): 2 to 3 feet high, narrow, willow-like leaves, small yellow flowers with bushy stamens.
Sunny Boulevard™ St John's Wort (Hypericum kalmianum 'Deppe'): A 2 to 3 feet high and wide shrub with small, bright yellow flowers.