Gemo St. John's Wort

Gemo St. John's Wort (Hypericum kalmianum 'Gemo')

Gemo St. John's Wort is a compact shrub that delivers a long run of bright yellow summer flowers on a tidy, mounded frame. The narrow, willow-like leaves add fine texture that keeps beds looking clean and intentional from spring through fall. It is an easy way to add reliable color and pollinator activity in sunny borders without a plant that needs constant attention. Once established, it handles typical garden conditions well and continues to look composed even between bloom flushes.

Distinctive Features

This selection forms a tightly branched, rounded mound with slender, blue-green to deep green foliage that reads refined in mixed plantings. Golden yellow flowers with prominent stamens appear in mid to late summer and often continue into early fall, extending seasonal color beyond many shrubs of similar size. The habit stays naturally compact and full, making it useful as a repeatable shrub that does not sprawl or open up quickly. Mature size is commonly about 2 to 3 feet tall and 2 to 3 feet wide.

Growing Conditions

• Sun: Full sun to part shade, with best flowering and density in full sun.
• Soil: Average, well-drained soil is ideal, and it adapts to many soils if drainage is reliable.
• Water: Keep evenly moist during establishment, then water during extended dry periods.
• USDA Zones: Zones 4 to 8.
• Mature Size: About 2 to 3 feet tall and 2 to 3 feet wide.
• Habit: Dense, mounded shrub with narrow, willow-like foliage.

Ideal Uses

• Focal Point: Use the long season of yellow bloom as a focal point near a walkway or patio where the flowers and pollinators can be enjoyed up close.
• Border Planting: Repeat in sunny borders to create a clean rhythm of foliage texture and dependable mid-season color.
• Foundation Planting: Place in front of taller shrubs for a tidy mid-layer that stays proportional and well-branched.
• Pollinator Garden: Include in sunny habitat plantings to support bees and other beneficial insects through summer.
• Low Hedge: Plant in a loose line to form a compact, flowering edge that reads neat without frequent trimming.

Low Maintenance Care

• Watering: Water consistently the first season to establish roots, then reduce frequency as the plant settles in.
• Mulching: Mulch to conserve moisture and reduce weeds, keeping mulch a few inches away from the stems.
• Pruning: Cut back in early spring to refresh the mound and encourage vigorous new growth and flowering.
• Fertilizing: Feed lightly in spring if needed, and avoid heavy fertilizing that can reduce flowering.
• Cleanup: Remove winter-damaged stems in spring to keep the plant dense and well-shaped.
• Airflow: Space for airflow and avoid consistently wet soils to keep foliage looking clean through the season.

Why Choose Gemo St. John's Wort?

• Long Bloom Season: Yellow flowers can continue from mid-summer into early fall for extended color.
• Compact, Tidy Habit: Dense mounding form stays neat and easy to place in smaller beds.
• Fine Foliage Texture: Narrow leaves add a refined look that pairs well with broader-leaved shrubs and perennials.
• Pollinator Friendly: Flowers attract bees and other beneficial insects during the summer season.
• Deer Resistance: Frequently less preferred by deer, though browsing can still occur.

If you want a compact shrub that stays tidy and delivers a strong summer flower show, Gemo St. John's Wort is a practical choice. Give it sun, reliable drainage, and a simple spring cutback to keep the mound full. It will reward you with clean texture, dependable yellow bloom, and an easy, four-season structure that supports the rest of the planting.