Erysimum scoparium, commonly known as Teide wallflower, offers an attractive presence in gardens. This subshrub is native to the Canary Islands, thriving in the montane zones of Tenerife and La Palma. Its ornamental appeal comes from its distinctive appearance and vibrant blooms, making it a desirable addition for gardeners.
Key Characteristics
Erysimum scoparium grows as a low, woody shrub, often wider than tall, reaching about 18 inches tall and 3 feet wide. Its foliage consists of narrow, linear, grey-green leaves, which may turn steely aubergine in cooler months. When squeezed, the leaves may emit a faint cabbage-like scent, characteristic of the Brassicaceae family.
Its most striking feature is its flowers, arranged on upright stems. These four-petaled blooms transition from dark purple buds to creamy-yellow flowers feathered with mauve, eventually becoming entirely mauve with age. These flowers appear for many months, from spring into summer, providing a long season of interest.
Ideal Growing Conditions
For Erysimum scoparium to thrive, providing the right environmental conditions is important. Full sun exposure is essential for optimal growth, ideally receiving at least six hours of direct sunlight daily. While it prefers full sun, some varieties tolerate partial shade.
Well-draining soil is required, as it is susceptible to root rot in waterlogged conditions. It adapts to various soil types but prefers sandy or loamy compositions, tolerating rocky soils with good drainage. A neutral to slightly alkaline pH is preferred. Once established, Erysimum scoparium is drought-tolerant, reflecting its adaptation to the dry, rocky soils of its native Canary Islands. During establishment, moderate watering is beneficial, allowing the soil to dry out almost completely between waterings.
It is hardy in USDA zones 8-10, though some sources indicate hardiness down to zone 6a. It prefers moderate temperatures, around 20°C (68°F), and tolerates dry conditions and mild winters. Originating from montane zones, it is adapted to subtropical climates and withstands heat and frost, making it a resilient choice for suitable regions.
Cultivation and Care
Maintenance for Erysimum scoparium is generally low, making it suitable for various garden settings. Regular deadheading of spent flowers encourages continuous blooming and prevents the plant from expending energy on seed production. This practice extends the flowering period significantly.
Pruning maintains the plant’s shape and vigor, preventing it from becoming overly woody or leggy. Light trimming after the first flush of blooms promotes a second round of flowering. More extensive pruning in late winter or early spring, just before new growth begins, rejuvenates the plant and encourages bushier development. Remove any dead or damaged stems and trim back overgrown areas during pruning.
It is not a heavy feeder, so fertilization should be sparing. A balanced, slow-release fertilizer (e.g., 5-10-10) can be applied lightly during the growing season, typically in early spring, to promote healthy growth and flowering. Over-fertilizing can lead to leggy growth at the expense of blooms. It is generally resistant to pests and diseases. However, aphids can occasionally appear on new growth, and in overly wet conditions, fungal problems like root rot or leaf spots may occur. Ensuring good air circulation and avoiding overhead watering mitigates fungal issues.
Benefits and Uses
Its ornamental value is a primary benefit, offering vibrant color and a long blooming season that can last for many months. Its evergreen foliage provides year-round interest. The delicate colors of its flowers, ranging from purple to creamy yellow, enhance garden aesthetics.
Beyond its visual appeal, Erysimum scoparium attracts beneficial pollinators like bees and butterflies, contributing to a healthy garden ecosystem. Its ability to draw these insects supports the pollination of other nearby plants. Its drought tolerance, once established, makes it an excellent choice for xeriscaping or low-water gardens, reducing the need for extensive irrigation. It is also well-suited for various landscape applications, including rock gardens, borders, and containers. Its resilience and adaptability to dry, poor soils also make it a viable option for coastal gardens or challenging areas.