Great St. Johnswort

(Hypericum ascyron)

Great St. Johnswort (Hypericum ascyron)

/

return to results
Previous Plant Next Plant

/

Hypericum ascyron image
scroll forward scroll backward
scroll forward scroll backward
Estimated Native Range
Species Map Help

Summary

Hypericum ascyron, commonly known as Great St. Johnswort, is a deciduous perennial herb native to moist meadows, stream banks, and open woodlands in the Northeastern USA, as well as Central and East Asia. It typically grows to a height of 2-5 feet (0.6-1.5 meters) and a width of 1-3 feet (0.3-0.9 meters). The plant features large, showy yellow flowers with prominent stamens that bloom in mid to late summer, adding a splash of color to the garden landscape.

Great St. Johnswort is valued for its ease of maintenance and the bright, cheerful flowers that attract pollinators such as bees and butterflies. It is often used in naturalistic plantings, wildflower gardens, and as a border plant. This species thrives in full sun to part shade and prefers consistently moist, well-drained soils. While generally pest-free, it can be susceptible to rust and leaf spot diseases. Gardeners should be aware that in some areas, it can spread aggressively and may require management to prevent unwanted naturalization.CC BY-SA 4.0

Plant Description

  • Plant Type: Herb
  • Height: 2-5 feet
  • Width: 1-3 feet
  • Growth Rate: Moderate
  • Flower Color: Yellow
  • Flowering Season: Summer
  • Leaf Retention: Deciduous

Growth Requirements

  • Sun: Full Sun
  • Water: Medium
  • Drainage: Medium, Slow

Common Uses

Bee Garden, Bird Garden, Butterfly Garden, Deer Resistant, Drought Tolerant, Edible*Disclaimer: Easyscape's listed plant edibility is for informational use. Always verify the safety and proper identification of any plant before consumption., Low Maintenance, Showy Flowers, Water Garden

Natural Habitat

Moist meadows, stream banks, and open woodlands

Other Names

Common Names: Giant St. John’s-Wort , Great St. John’s-Wort , Millepertuis Ascyron , Millepertuis Faux-Ascyrum , Millepertuis À Grande Fleur , Millepertuis À Grandes Fleurs , Kransjohannesört , 물레나물 , 連翹;湖南連翹;黃海棠

Scientific Names: Hypericum ascyron , Hypericum ascyron f. angustifolium , Hypericum ascyron var. adamii , Hypericum sachalhense

GBIF Accepted Name: Hypericum ascyron L.