Tradescantia Zwanenburg Blue, commonly known as Spiderwort, is an elegant perennial valued for its extended blooming period and vibrant color palette. This cultivar is distinguished by its deep, rich blue-violet, three-petaled flowers, which feature prominent yellow stamens at their center. It develops a neat, clump-forming habit with arching, grass-like, mid-green foliage that remains attractive throughout the growing season. This guide details the specific requirements for growing and maintaining the ‘Zwanenburg Blue’ Spiderwort.
Establishing the Plant Location and Soil
Tradescantia Zwanenburg Blue requires fertile, moisture-retentive, and well-draining soil. The ideal planting medium should be humus-rich, incorporating organic matter to maintain consistent dampness without becoming waterlogged. While the plant tolerates a range of soil types, including clay, a neutral to slightly acidic pH between 6.0 and 7.5 is preferred for optimal nutrient uptake.
Ensure the planting site allows for adequate drainage to prevent standing water, which can lead to root rot. This Spiderwort grows into a spreading clump, reaching up to 24 inches wide. Plant the crown at the soil surface, firming the soil gently around the roots to eliminate air pockets. Space individual plants 18 to 30 inches apart to accommodate their mature size and ensure sufficient air circulation, which helps prevent fungal issues.
Essential Environmental Needs
Light intensity directly influences the plant’s flowering performance and health. Tradescantia Zwanenburg Blue thrives best in full sun to partial shade, requiring at least four to six hours of direct sunlight daily. In regions with intense afternoon heat, providing light afternoon shade prevents foliage scorching. Too much shade will result in reduced flower production and cause stems to become elongated and weak.
A consistent watering schedule is necessary, especially during dry periods, as this perennial is not highly drought-tolerant. The soil should be kept evenly moist, though allowing the top layer to partially dry out between waterings is important to avoid over-saturation near the crown. This species is hardy in USDA Hardiness Zones 3 through 9. The plant tolerates typical summer temperatures and humidity, though watering adjustments are necessary as temperatures rise due to its preference for consistently moist soil.
Routine Maintenance and Seasonal Care
To encourage continuous bloom from early summer into late summer, regular deadheading (removal of spent flowers) is recommended. Although each flower lasts only one day, the plant produces successive blossoms over many weeks. Removing faded blooms prevents the plant from diverting energy into seed production and helps manage its prolific self-seeding tendency.
A mid-season cutback, often called the “Tradescantia chop,” manages the plant’s appearance and growth habit. When foliage becomes leggy or sparse after the first major flush of flowers, cut the entire plant back by about one-third of its height. This stimulates a flush of new growth and a second round of blooms. Spiderworts are not heavy feeders; supplemental feeding is often unnecessary in rich garden soil. If the soil is lean, apply a balanced, all-purpose fertilizer once a month during the active spring and summer growing season.
While generally resilient, the plant may occasionally face common garden pests like aphids, slugs, snails, and vine weevils, or diseases such as fungal leaf spot and rust. Maintaining good air circulation through proper spacing and avoiding overhead watering helps minimize the risk of fungal infections. For winter preparation in colder zones, the herbaceous perennial will die back to the ground; cut the foliage back late in the season after it has withered completely. In the lower end of its hardiness range, a layer of protective mulch applied around the base can insulate the crown.
Propagation Techniques
Division is the most reliable and straightforward method for increasing the stock of Tradescantia Zwanenburg Blue. This process involves lifting a mature clump from the ground, preferably in early spring before new growth begins or in the autumn after flowering. The root ball is separated into smaller sections, ensuring each new piece retains a healthy portion of roots and several growing shoots. Division also rejuvenates older, less vigorous plants that have become overcrowded.
Stem cuttings offer another easy way to propagate this plant, which is capable of rooting quickly. To take a cutting, use a clean, sharp tool to snip a stem section about four to six inches long, making the cut just below a leaf node. Remove the lower leaves so that at least one node is exposed. Cuttings can be placed directly into moist potting mix or suspended in water until roots develop. Once roots are one to two inches long, the cutting can be transplanted into a permanent location.