Alyssum ‘Clear Crystal® Purple Shades’

Alyssum ‘Clear Crystal® Purple Shades’

Alyssum ‘Clear Crystal® Purple Shades’, commonly known as Sweet Alyssum or Purple Sweet Alyssum, is a vibrant, fragrant annual in the mustard family, Brassicaceae. Gardeners prize it for its stunning clusters of star-shaped purple flowers with deep purple eyes that appear from mid-spring through mid-fall. This compact, trailing plant produces grayish-green foliage that remains attractive throughout the season, making it perfect for borders, containers, and mass plantings. Its cheerful blooms attract bees, butterflies, and hummingbirds, while remaining deer-resistant.

This variety belongs to the Lobularia maritima species, a plant native to the Mediterranean region but widely cultivated worldwide. ‘Clear Crystal® Purple Shades’ is a tetraploid hybrid, giving it extra vigor, heat tolerance, and a longer flowering period compared to standard alyssum. Breeders at Ball Seed developed this series to combine superior bloom size, durability, and continuous flowering, making it a favorite for ornamental use.

Appearance and Growth Habit of ‘Clear Crystal® Purple Shades’

Clear Crystal® Purple Shades grows as a dense, herbaceous annual with a mounded and trailing habit. The plants reach approximately 6–8 inches (15–20 cm) tall and spread 12–14 inches (30–36 cm) wide. Its foliage consists of tiny, narrow, grayish-green leaves that form a fine-textured groundcover or filler in containers. The plant’s cascading growth habit makes it ideal for hanging baskets, window boxes, and as a “spiller” in the popular “thriller, filler, spiller” container design.

Flowers emerge in tight clusters along the stems, covering the foliage with vibrant purple blooms that feature darker purple eyes. Each small, star-shaped flower measures around 1 cm (0.4 in) across. The flowers’ fragrance adds an extra sensory appeal to gardens, attracting pollinators and enhancing outdoor spaces. Blooming occurs in flushes throughout the growing season, from early spring until the first frost, providing long-lasting color and visual interest.

Flowering Season

Clear Crystal® Purple Shades offers an exceptionally long blooming period. The plant begins flowering in early spring, and with proper care, it continues to bloom intermittently through autumn. Although extremely heat-tolerant, flowering may slow during peak summer heat in warmer climates. As temperatures cool, the plant quickly resumes full flowering, ensuring constant visual impact in borders, containers, and mass plantings.

Deadheading spent flowers enhances continued blooming and maintains a tidy appearance. Additionally, shearing the plant by half in mid-summer encourages fresh growth and a second flush of blooms, keeping the display dense and vibrant.

Plant Family and Synonyms

Clear Crystal® Purple Shades belongs to the Brassicaceae family, also known as the mustard family. This family includes well-known vegetables such as broccoli, cabbage, kale, and radishes, along with ornamental plants like alyssum. Other common names and synonyms for this variety include Sweet Alyssum, Purple Sweet Alyssum, and its cultivar designation, ‘Clear Crystal® Purple Shades’. These names are useful for gardeners searching for the plant online or in catalogs.

Landscape Uses

This alyssum variety excels in multiple landscape applications. It performs beautifully in mass plantings, forming low carpets of color. Gardeners often use it in rock or alpine gardens, border edging, groundcover, and general garden use. The trailing habit also makes it perfect for hanging baskets and container plantings, where it spills gracefully over the edges. The combination of dense foliage and continuous blooms creates a soft, delicate texture that complements taller plants and structural garden features.

How to Grow Alyssum ‘Clear Crystal® Purple Shades’

Sunlight

Plant Clear Crystal® Purple Shades in full sun to partial shade. While it tolerates light afternoon shade, the plant performs best with at least 6 hours of direct sunlight daily. Adequate light promotes dense growth and prolific flowering.

Soil

This alyssum thrives in well-draining soil with a moderate fertility level. It tolerates a wide range of soil types, including sandy, loamy, or slightly clayey soils. Optimal pH ranges from 5.8 to 6.2. Adding compost or organic matter before planting improves soil structure, fertility, and water retention, particularly in container plantings.

Watering

Maintain evenly moist soil for optimal growth. Water the plants at the base to avoid wetting the foliage, which reduces the risk of disease. In containers, water more frequently as they dry faster than in-ground plantings. Allow the top 2 inches (5 cm) of soil to dry slightly between waterings to prevent root rot and leaf blight.

Fertilizing

Clear Crystal® Purple Shades is a moderate feeder. Apply a balanced, water-soluble fertilizer once a month during the growing season to stimulate vigorous growth and continued flowering. Fertilizing after the first bloom flush ensures strong, healthy plants with abundant flowers. Adding a light layer of compost or organic mulch around the base can also provide nutrients and conserve soil moisture.

Pruning and Deadheading

Deadhead spent flowers to encourage new blooms and maintain plant tidiness. Mid-summer shearing by half promotes fresh growth and extends flowering into the late season. Pinching back young plants can help maintain a compact, mounded habit and encourages fuller foliage coverage.

Propagation of ‘Clear Crystal® Purple Shades’

Propagate Clear Crystal® Purple Shades by cuttings for best results, though the plant can also be grown from seed in early spring. For cuttings, take healthy semi-ripe stems, remove the lower leaves, and plant them in a well-draining propagation medium. Keep the cuttings moist in a warm, humid environment until roots develop. While propagation is possible, remember that some cultivated varieties may be subject to restrictions or patents.

Pest and Disease Management

Clear Crystal® Purple Shades is generally hardy and low-maintenance, but gardeners should monitor for occasional pests and diseases.

• Aphids and Thrips: Check leaves and flowers for signs of feeding. Treat infestations with insecticidal soap, neem oil, or a strong water spray.
• Downy Mildew: Prevent this fungal issue by watering early in the day at the plant base and ensuring good airflow between plants. Avoid copper-based fungicides, as they can harm alyssum.
• Environmental Tolerance: This alyssum handles urban pollution, salt exposure, and mild drought. Its toughness makes it suitable for inner-city gardens, coastal areas, and challenging landscapes.

Environmental Tolerances and Cold Hardiness

Clear Crystal® Purple Shades tolerates temperatures down to 0°C (32°F), making it hardy as an annual in temperate climates. While it thrives in full sun, it can tolerate light shade and adapts to various urban and garden conditions. Its heat tolerance surpasses older alyssum varieties, and it recovers quickly from mild drought or temporary stress.

Garden Design Tips

Use Clear Crystal® Purple Shades in layered garden designs to maximize its trailing habit. Plant it near taller plants to act as a colorful carpet or along garden edges to soften hard lines. In containers, combine it with upright plants for vertical contrast and centerpieces for patios or decks. Its fine texture, fragrance, and pollinator appeal make it an excellent addition to cottage gardens, mixed borders, or wildlife-friendly landscapes.

Summary

Alyssum ‘Clear Crystal® Purple Shades’ combines beauty, fragrance, and resilience in one compact plant. Its long bloom period, low-maintenance habit, and tolerance of heat, salt, and urban conditions make it a reliable choice for gardens, containers, and landscapes. By planting it in full sun, providing well-draining soil, and performing routine deadheading and light pruning, gardeners can enjoy vibrant purple blooms from early spring until frost. Its trailing form adds visual interest and texture to any planting scheme, while attracting bees, butterflies, and hummingbirds.

This Sweet Alyssum variety is ideal for gardeners seeking a fragrant, colorful, and durable annual that provides both aesthetic and ecological benefits. With proper care, Clear Crystal® Purple Shades will thrive in beds, borders, hanging baskets, and containers, creating continuous color and fragrance throughout the growing season.