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Great St. John's Wort
Hypericum ascyron
Great St. John's Wort adds a burst of cheerful yellow to the garden with its large, sunny flowers that bloom in mid-summer. This robust perennial can reach up to 5 feet in height, offering a bold vertical element to the landscape. The flowers, up to 3 inches across, feature a profusion of stamens that create a frilly, eye-catching center. It's a wonderful choice for attracting pollinators like bees and butterflies and fits well in naturalistic settings or as a background plant in perennial borders. Thriving in full sun to partial shade, it adapts to a range of soil conditions but prefers moist, well-drained sites.
Details
Height24” - 60”
Spread18"
Bloom SeasonJune – August
Soil Types
Clay
Loam
Sand
Soil Moisture
Moist
Wet
Sun Exposure
Full Shade
Part Sun
Full Sun
Range Map
Available
Not available
Ecological Benefits
Maintenance Tips
- Deadhead to promote continued blooming and prevent self-seeding.
- Minimal care needed in general; monitor for rust and leaf spots and treat as necessary.



