Shrubby St. John's wort

Shrubby St. John's wort beginning to flower.

Shrubby St. John's wort is a low to medium-sized native shrub reaching 3 to 4 feet high. The bright yellow flowers with a profusion of yellow stamens look like fireworks. The exfoliating bark and attractive seed capsules add winter interest to the landscape.

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.

Botanical name:

Hypericum prolificum

All Common Names:

Shrubby St. John's wort

Family (English):

Hypericum

Family (Botanic):

Hypericaceae

Tree or Plant Type:

  • Shrub

Native Locale:

  • Chicago area,
  • Illinois,
  • North America

Landscape Uses:

  • Foundation,
  • Hedge,
  • Massing,
  • Mixed border,
  • Patio/sidewalk

Size Range:

  • Small shrub (3-5 feet)

Light Exposure:

  • Full sun (6 hrs direct light daily),
  • Partial sun/shade (4-6 hrs light daily)

Hardiness Zones:

  • Zone 4,
  • Zone 5 (Chicago),
  • Zone 6,
  • Zone 7,
  • Zone 8

Soil Preference:

  • Moist, well-drained soil

Tolerances:

  • Dry sites,
  • Occasional flooding,
  • Alkaline soil,
  • Clay soil

Season of Interest:

  • Early summer,
  • Mid summer,
  • Late summer

Flower Color & Fragrance:

  • Yellow

Shape or Form:

  • Mounded,
  • Multi-stemmed,
  • Round

Growth Rate:

  • Slow

More Information:

Size & form

A mounded, 3 to 4 feet high and wide shrub with stiff erect stems.

Tree & Plant Care

Best in full sun to part shade.
Adaptable to most soil pH, including heavy clay.
Flowers on new wood, prune in spring.
Can be short-lived in wet winters.

Disease, pests, and problems

None serious.

Disease, pest, and problem resistance

Drought, clay, rabbit and deer resistant, tolerant of aerial salt spray.

Native geographic location and habitat

C-Value: 9
Eastern U. S. including IL, IA NJ, and GA.

Attracts birds, pollinators, or wildlife

Birds, butterflies and bees.

Bark color and texture 

Young twigs are slender, gray and ridged, older stems exfoliate exposing a bronzy inner bark.

Leaf or needle arrangement, size, shape, and texture

Opposite, linear to lanceolate, 4 inches long and 1/2 inch wide bright green leaves.
Very short petiole with leaf-like bracts at base of the leaves.

Flower arrangement, shape, and size

Small, 3/4 to 1-inch wide yellow flowers with many showy stamens, borne in terminal or in stem axil in early summer.

Fruit, cone, nut, and seed descriptions

A 3-chambered, upright, brown capsule, persistent  throughout winter.

Cultivars and related species 

Albury Purple Tutsan (Hypericum androsaemum 'Albury Purple'): Low mounding, 2 to 3 feet high and wide, rich velvety purple leaf tips, yellow flowers and attractive dark red fruit capsules.

Location of Hypericum prolificum (Shrubby St. John's wort) at the Arboretum