Masterwort (Astrantia major 'Rubra')
Astrantia major 'Rubra' (Masterwort) offers claret-red pincushion flowers from May to July in zones 4-7, thriving in part shade.
Complete Plant Information
Overview
Astrantia major ‘Rubra’, commonly known as Masterwort, is a highly valued herbaceous perennial prized for its unique, intricate blooms that add texture and lasting color to shaded gardens. This cultivar features distinct domed umbels of silver-tinged, claret-red florets, subtended by a showy ruff of papery bracts, making it an excellent focal point. Masterwort performs best when provided with consistently moist, rich soil and partial shade conditions, allowing its basal clump of deeply divided leaves to flourish. Gardeners appreciate Astrantia major ‘Rubra’ not only for its extended late spring to early summer display but also for its reliability as a long-lasting cut flower and its tendency to form attractive, non-invasive colonies over time.
Fast Facts
- Plant Family: Apiaceae
- Plant Type: Herbaceous perennial
- Hardiness Zones: USDA Zones 4-7
- Size at Maturity:
- Height: 1.5-2.5 ft
- Spread: 1-1.5 ft
- Bloom Time: May to July
- Bloom Description: Red
- Sun Exposure: Part shade
- Water Needs: Medium to wet
- Maintenance Level: Medium
How to Grow
Plant Astrantia major ‘Rubra’ during cool periods, preferably in spring or fall, ensuring the location provides organically rich, well-drained soil. While it prefers partial shade, this stunning Masterwort may tolerate full sun only in temperate climates where soils remain consistently moist throughout the growing season. Establishing consistent moisture is crucial, as these plants do not tolerate drying out and thrive best where the soil is uniformly damp, though not waterlogged.
Maintenance for Astrantia major ‘Rubra’ is generally moderate. Water regularly to keep the soil consistently moist, especially during hot, dry periods, which is vital for optimal summer performance. Deadheading the spent flowerheads immediately after blooming is recommended if you wish to prevent self-seeding, and this practice may also encourage a slightly prolonged bloom period into the summer months.
Ensure the plant receives sufficient moisture during summer, as cooler night temperatures dipping below 70°F encourage the best growth habit for this European native. If you notice the plant struggling in high summer heat without adequate moisture, consider moving it to a cooler, shadier spot the following year.
Landscape Uses
The upright structure and unique floral texture of Astrantia major ‘Rubra’ make it exceptionally versatile in landscape design. It excels when placed in the part shade areas of mixed perennial borders, providing necessary vertical contrast among lower-growing foliage plants. The requirement for moisture steers ideal placement towards woodland margins, below the high canopy of open trees, or along the banks of stream gardens, provided the plant remains above the water level.
For a naturalized effect, allow the Masterwort to self-seed gently; it complements wild or cottage garden styles beautifully where it can spread slowly via stolons to fill open spaces without becoming intrusive. Furthermore, the durable, papery bracts of the spent blooms make Astrantia major ‘Rubra’ an excellent choice for both fresh and dried flower arrangements, adding interest long after the initial peak.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
The species, Astrantia major, is an upright, herbaceous perennial native to European mountain meadows and moist woodland clearings. The specific cultivar, Astrantia major ‘Rubra’, is celebrated for its compact habit and claret-red flowers held above deeply lobed, medium green basal foliage. The structure, featuring a delicate, pincushion center subtended by a prominent ruff of papery bracts, remains attractive even after the florets fade.
Tolerances
- Wet Soil
Potential Problems
This Masterwort cultivar generally avoids serious insect or disease issues, which simplifies its care routine. Slug visitors are an occasional nuisance, particularly when conditions are damp and sheltered. To manage slugs, apply standard organic controls such as diatomaceous earth barriers or iron phosphate baits around the base of the plants, focusing efforts during periods of new growth in the spring.
Frequently Asked Questions
What hardiness zones is Masterwort suitable for?
Astrantia major ‘Rubra’ is suitable for USDA Zones 4 through 7.
How large does Astrantia major ‘Rubra’ grow?
This compact cultivar typically achieves a height between 1.5 and 2.5 feet, with a spread reaching 1 to 1.5 feet wide.
When does Masterwort bloom?
Astrantia major ‘Rubra’ typically displays its characteristic red flowers from May through July.
What sun exposure does Astrantia major ‘Rubra’ need?
This plant performs best in part shade conditions, though it can tolerate more sun if soil moisture is kept consistently high.
Conclusion
Astrantia major ‘Rubra’ provides essential structure and unique, long-lasting color for shaded garden spaces where moisture is abundant. Protecting this Masterwort from drying out during hot summers is the key to horticultural success, rewarding attentive gardeners with dependable floral displays. Check your site conditions against USDA Zones 4-7 and plan your planting for enhanced visual interest in your cottage garden scheme this season.
Companion Planting for Moist Shade
Selecting appropriate companions that share the moisture and shade preferences of Astrantia major ‘Rubra’ is crucial for a harmonious border. Hostas of contrasting leaf color, such as those with blue or gold variegation, work well beneath the airy flowers of the Masterwort. Ferns, particularly Japanese Painted Ferns or Maidenhair Ferns, echo the woodland aesthetic and appreciate the uniformly moist soils that Astrantia demands.
Groundcovers that tolerate shade and moisture, such as native wild ginger (Asarum species) or lamium, can help conserve soil moisture around the base of the Masterwort, reducing evaporation and suppressing potential weed competition. This combination creates a rich tapestry of texture suitable for woodland edges or north-facing borders.
Seasonal Care Calendar
Spring preparation involves cleaning up any winter debris and ensuring the soil is rich with compost, as Astrantia major ‘Rubra’ benefits greatly from high organic matter. Begin consistent watering once new growth emerges, and monitor actively for slug activity during this tender period.
Mid-summer care centers almost entirely on hydration; aim to keep the soil consistently moist, especially if bloom time extends beyond initial expectations. If you wish to encourage rebloom or tidy the appearance, deadhead faded flower stalks promptly.
In autumn, little intervention is required unless deadheading self-seeding plants was neglected. The basal foliage of the Masterwort usually remains attractive late into the year, providing necessary winter interest before the plant enters dormancy.
