St. John's wort (Hypericum × moserianum 'Tricolor')

Overview

The striking Hypericum × moserianum ‘Tricolor’ is a highly desirable cultivar of St. John’s wort, prized globally for its variegated foliage that edges the oval leaves in white, often showing a rosy blush. This compact, mounded shrub provides season-long interest, setting off its bright buttercup-yellow flowers that appear from mid-summer well into the fall months. It offers reliable color in mixed borders or rock gardens, making it much more dynamic than standard green-leafed selections.

This specific St. John’s wort hybrid between H. Calycinum and H. Patulum establishes a gently arching habit, typically reaching up to 2.5 feet tall in warmer areas. While it maintains its evergreen status through milder winters, its cultural needs are straightforward: average, well-drained soil and a location receiving full generosity of sun or bright, partial shade. Because of its appealing form and reliable summer show, Hypericum × moserianum ‘Tricolor’ is a versatile addition to the intermediate layer of any landscape design.

Fast Facts

• Plant Family: Hypericaceae
• Plant Type: Deciduous shrub
• Hardiness Zones: USDA Zones 6-9
• Size at Maturity:
  • Height: 1-2.5 ft
  • Spread: 1.5-3 ft
• Bloom Time: July to September
• Bloom Description: Yellow
• Sun Exposure: Full sun to part shade
• Water Needs: Medium
• Maintenance Level: Medium

How to Grow

Planting Hypericum × moserianum ‘Tricolor’ should ideally occur in spring or early fall, allowing the roots time to establish before the stresses of summer heat or deep winter cold. This St. John’s wort adapts readily to various soil types but requires good drainage; it thrives particularly well in sandy soils provided it receives the recommended sun exposure. Ensure the site offers at least a few hours of direct sun daily to maintain the best variegation and floral display.

Watering should be consistent, particularly during the first growing season, as this variety prefers medium moisture levels. Avoid letting the soil become waterlogged, which can lead to root issues, but do not allow prolonged drought, especially when grown in hot, exposed locations enjoying full sun. Fertilization is rarely necessary; an annual light application of a balanced, slow-release fertilizer in early spring is usually sufficient if your soil quality is poor.

Pruning is key to maintaining the appearance of this shrub. In warm winter climates where the plant remains evergreen, shear lightly in early spring to shape and encourage fresh, dense growth. Conversely, in colder zones, the plant may die back to the ground. In this case, cut all stems back to the base in early spring before new growth emerges, treating it much like an herbaceous perennial. Gardeners in Zone 5 should provide winter mulch and protection, observing that Hypericum × moserianum ‘Tricolor’ is not reliably hardy there.

Landscape Uses

The dense, low-growing habit of this St. John’s wort makes it exceptionally useful along pathways or defining the edges of perennial beds. While it performs well as an informal hedge in milder regions, its smaller stature in colder climates (where it may only reach 12-15 inches) suits it perfectly as a neat, low edger. The bright yellow flowers contrast beautifully against deep green or purple foliage plants used nearby.

Consider pairing Hypericum × moserianum ‘Tricolor’ with plants that require similar sun and water conditions. Low-growing ornamental grasses or late-blooming sedums offer textural diversity for rock gardens where this cultivar excels. Its variegated leaves ensure visibility even when the plant is not in bloom, linking the garden spaces cohesively.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Hypericum × moserianum is a cultivated hybrid of St. John’s wort resulting from a cross between H. Calycinum and H. Patulum. Mature plants have gently arching stems and a rounded habit, reaching 2-3’ tall with an equal spread, showcasing golden yellow flowers up to 2” wide from mid-summer into early fall. This St. John’s wort hybrid cultivar, Hypericum × moserianum ‘Tricolor’, is notable for its small, mounded shape, reddish stems, and handsome variegated, oval leaves edged in white. Flowers feature five buttercup-like petals and numerous dense, bushy stamens.

Tolerances

This cultivated hybrid is generally disease-free and shows good resilience in the garden when sited correctly.

Potential Problems

Serious insect or disease problems are rare for the St. John’s wort cultivar Hypericum × moserianum ‘Tricolor’. Its primary cultural challenge relates to winter survival in colder zones; ensuring sharp drainage and providing adequate winter mulch in areas near the Zone 6 boundary will mitigate nearly all potential issues. Monitor for signs of stress if planted outside its noted hardiness range.

Frequently Asked Questions

What hardiness zones is St. John’s wort suitable for?

The reliable growing range for Hypericum × moserianum ‘Tricolor’ is USDA Zones 6 through 9.

How large does Hypericum × moserianum ‘Tricolor’ grow?

In mature, warm-winter settings, this shrub typically reaches 1 to 2.5 feet in height with a spread between 1.5 and 3 feet. In very cold winters, it may die back, resulting in a smaller, 12 to 15-inch perennial-like form the following spring.

What sun exposure does Hypericum × moserianum ‘Tricolor’ need?

For the best performance, plant this cultivar where it receives full sun to light part shade. Reduced light will diminish the brightness of the variegated leaf margins.

When does St. John’s wort bloom?

This variety offers a long bloom period, typically starting in July and continuing to flower sporadically through September, displaying cheerful yellow blossoms.

Conclusion

The variegated foliage and mid-summer yellow flowers make Hypericum × moserianum ‘Tricolor’ an indispensable, low-maintenance shrub for adding texture and year-round interest to the landscape. This specific St. John’s wort hybrid offers reliable performance and color contrast for borders and rockeries. Always ensure your location falls within USDA Zones 6-9 for best results, or prepare for spring pruning if winter dieback occurs.

Companion Planting

Successful companion planting relies on matching the sun and water requirements of this moderately thirsty shrub. Grouping Hypericum × moserianum ‘Tricolor’ with other sun-loving, drought-tolerant perennials like Russian Sage (Perovskia) or certain varieties of ornamental grasses helps create a unified, low-fuss planting scheme. Alternatively, plant it near darker foliage plants, such as ninebark cultivars (Physocarpus), whose deep burgundy color will dramatically set off the pale, rosy-edged leaves of the variegated St. John’s wort.

In borders, use it as a transitional plant between taller background shrubs and low groundcovers. Because it spreads moderately (up to 3 feet), it can serve as a living mulch, suppressing weeds while maintaining a formal or informal hedge line that brightens shaded edges with its unique leaf pattern.

Seasonal Care Calendar

Early Spring (Late Freeze): This is the crucial time for pruning. In colder climates (Zone 6), cut back all dead, woody stems to about 2-3 inches above the soil line, allowing the new shoots of Hypericum × moserianum ‘Tricolor’ to emerge cleanly. In warmer zones, lightly trim away any damaged or leggy stems to maintain the mounded shape. Ensure the soil is cleared of fallen debris to prevent fungal issues starting under old leaf litter.

Mid-Summer (Peak Bloom): Monitor moisture levels, especially if planted in full sun or sandy soil, as the plant requires medium water consistently during this phase. Deadheading is generally not essential, as spent flowers often drop cleanly, but removing heavily faded clusters can sometimes encourage a very minor rebloom flush. No significant pest scouting is usually required due to the plant’s inherent resistance.

Late Fall/Early Winter: If you are in Zone 6 or 5, prepare for winter dormancy or dieback. Apply a 2-3 inch layer of protective mulch (shredded bark or compost) around the base, avoiding piling it directly against the crown. This helps insulate the roots against temperature fluctuations; remember that robust winter hardy specimens begin as well-established plants the prior growing season.