Spiderwort (Tradescantia (Andersoniana Group) 'Snowcap')

Overview

The pure white blooms of Tradescantia (Andersoniana Group) ‘Snowcap’ bring striking contrast to the garden landscape, emerging from May through July. This clump-forming herbaceous perennial, commonly known as Spiderwort, is highly valued for its ability to thrive in challenging moist conditions where other plants might struggle. Its beauty lies not only in the flowers but also in the architectural, iris-like foliage.

As a hardy hybrid member of the Andersoniana Group, Tradescantia (Andersoniana Group) ‘Snowcap’ offers reliable seasonal interest. It performs best when given ample moisture, making it architecturally significant near water features or in rain garden designs. Gardeners appreciate its relatively easy care profile, though management of summer decline is key to maintaining its aesthetic appeal throughout the season.

This Spiderwort cultivar typically reaches 1 to 2 feet high and wide, offering robust but not overly aggressive perennial coverage. The flowers, while individually short-lived, are produced in succession, ensuring a long period of visual appeal. If you need reliable texture and dependable white color for damp sections of your yard, Tradescantia (Andersoniana Group) ‘Snowcap’ is an excellent foundational choice.

Fast Facts

• Plant Family: Commelinaceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 4-9
• Size at Maturity:
  • Height: 1-2 ft
  • Spread: 1-2 ft
• Bloom Time: May to July
• Bloom Description: White
• Sun Exposure: Full sun to part shade
• Water Needs: Medium to wet
• Maintenance Level: Medium

How to Grow

Plant Tradescantia (Andersoniana Group) ‘Snowcap’ during the spring or fall in a location receiving full sun to partial shade. It performs exceptionally well in average, well-drained soil, however, it is notably tolerant of wet, boggy conditions, preferring moist, acidic, and humus-rich environments. Ensure the planting site accommodates its need for consistent moisture, particularly during dry spells.

Watering should be vigilant during establishment to keep the soil consistently moist. Once established, the medium to wet water requirements of this Spiderwort mean you should water deeply if the soil begins to dry out, especially in hotter weather. Fertilization is rarely required; rich, humusy soil usually provides sufficient nutrients, allowing the plant to focus energy on foliage and flower production.

Deadheading spent flower clusters promptly encourages a longer bloom period by prompting new buds to open. A crucial maintenance step occurs as summer heat peaks: the foliage of the Spiderwort tends to decline or sprawl unattractively. At this stage, cut the plants back hard, almost to the ground. This severe pruning stimulates healthy new growth and often triggers a renewed flush of bloom late in the summer into the fall. Divide overgrown clumps every few years to maintain vigor.

Landscape Uses

Tradescantia (Andersoniana Group) ‘Snowcap’ excels in moist landscape environments where traditional border plants might falter. Its tolerance for wet soil makes it a cornerstone plant for rain gardens, helping manage runoff and beautifying damp slopes or drainage areas adjacent to streams or ponds. It integrates seamlessly into naturalized settings and open woodland garden designs, providing vertical interest among shade-tolerant groundcovers.

When used in traditional borders, this Spiderwort acts as a beautiful textural element, contrasting well with ferns or hostas that appreciate similar moisture levels. While it is primarily an upright, herbaceous perennial, avoid using it in formal hedges due to its tendency to sprawl later in the summer if not pruned. The crisp, pure white flowers of Tradescantia (Andersoniana Group) ‘Snowcap’ act as bright accents against deeper greens and blues found in companion plantings.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Tradescantia, commonly called spiderworts, is a genus of about 65 species of herbaceous perennials from North, Central and South America. They are grown for their showy, three-petaled flowers and attractive foliage. The Andersoniana Group of hybrid spiderworts are some of the most common perennial spiderworts seen in cultivation. ‘Snowcap’ is a clump-forming herbaceous perennial which typically grows 1-2’ tall, featuring large, pure white, three-petaled flowers accented by contrasting yellow stamens. Individual flowers open for only one day in succession, contributing to its extended season of color from late May into July.

Tolerances

• Wet Soil

Potential Problems

This hardy plant generally avoids serious insect or disease issues, making it a reliable garden performer. However, younger, tender shoots of the Spiderwort are appealing targets for surface feeders. Be vigilant for damage caused by snails and caterpillars, which can chew holes in emerging foliage early in the season.

The primary cultural challenge with Tradescantia (Andersoniana Group) ‘Snowcap’ is its mid-season habit. As mentioned in care guides, the foliage frequently sprawls or declines substantially once the intense heat of summer sets in or if moisture levels drop. Proactive, hard pruning after the initial flush of bloom is the essential management technique to prevent this unattractive sprawl and encourage fresh growth.

Frequently Asked Questions

What hardiness zones is Spiderwort suitable for?

Tradescantia (Andersoniana Group) ‘Snowcap’ is reliably hardy in USDA Zones 4 through 9. Ensure your location falls within this range for optimal perennial growth.

How large does Tradescantia (Andersoniana Group) ‘Snowcap’ grow?

This herbaceous perennial typically achieves a height between 1 and 2 feet, spreading to a similar width of 1 to 2 feet at maturity.

What sun exposure does Spiderwort need?

For the best performance and most abundant bloom, Tradescantia (Andersoniana Group) ‘Snowcap’ prefers full sun to part shade conditions.

When does Spiderwort bloom?

The bloom time for this variety is generally from May through July, showcasing distinctive white, three-petaled flowers.

Conclusion

The Tradescantia (Andersoniana Group) ‘Snowcap’ provides exceptional reliability and pristine white color, particularly benefiting gardens with moist soil conditions or those requiring rain garden specimens. This versatile Spiderwort meets the need for texture and mid-height structure across a wide range of hardiness zones. Before planting, assess your site’s moisture levels and plan for that necessary mid-summer hard cutback to ensure continued excellent performance from your Tradescantia (Andersoniana Group) ‘Snowcap’.

Companion Planting

Companion planting successfully with Spiderwort involves pairing it with other moisture-loving perennials that share similar light requirements. Consider placing it alongside moisture-tolerant flowering perennials like Astilbe, which provides contrasting feathery texture, or Siberian Iris (Iris sibirica), which offers similar iris-like foliage structure. For color contrast in a rain garden setting, deep purple or blue blooming flowers, such as Joe Pye Weed or certain varieties of hardy Lobelia, will make the pure white flowers of Tradescantia (Andersoniana Group) ‘Snowcap’ truly pop visually.

Propagation Tips

Propagation for this perennial is straightforward, primarily achieved through clump division. When clumps of Tradescantia become overcrowded—usually every 3 to 4 years—the plant begins to flower less prolifically. Late fall after the foliage has died back, or early spring before new growth starts, are the best times to lift the clump using a garden fork. Carefully separate the root ball into smaller sections, ensuring each division has viable roots and a few growth nodes. Replant these divisions immediately into prepared, moist soil at the original depth to establish new plants easily.