The wallflower (Erysimum cheiri) is a spindly, flowering herb with a penchant for growing in cliff crevices. It blooms in spring with an abundance of fragrant flowers that can range in shades of yellow, orange, red, purple, brown, or white. Many gardeners prefer to plant wallflower as a biennial, sowing seeds one year in order to protect the roots from a common infection known as clubfoot.
I. Appearance and Characteristics
Erysimum cheiri, syn. Cheiranthus cheiri, the wallflower, is a species of flowering plant in the family Brassicaceae (Cruciferae), native to Greece, but widespread as an introduced species elsewhere. It is also treated as a hybrid under the name Erysimum × cheiri. It is widely cultivated as a garden plant.
The common name “wallflower” attaches to all cultivars of this plant, as well as other species within the genus Erysimum and the former genus Cheiranthus.
This is a herbaceous perennial, often grown as a biennial, with one or more highly branching stems reaching heights of 15–80 cm (6–31 in). The leaves are generally narrow and pointed and may be up to 20 cm (8 in) long. The upright to ascending shoot axes can lignify in the lower area. The lower leaves are in a rosette and have a short stalk. The leaf blade is up to 10 centimeters long, lanceolate and has double-stranded hair. The leaves along the stem axis are crowded, much smaller and almost sessile.
The top of the stem is occupied by a club-shaped inflorescence of 10 to 30 strongly scented, nectar-bearing flowers, the crown of which is yellow to brown or reddish in color due to the interaction of the red anthocyanin cyanidin with various carotenoids, and golden yellow in the wild form. Each flower has purplish-green sepals and rounded petals which are two to three centimeters long and in shades of bright yellows to reds and purples. The flowers are quite large with a diameter of 20, rarely up to 25 millimeters. The scar is deeply bilobed, the lobes are later curved back. Pollination is carried out by bees and bumblebees.
The flowers fall away to leave long fruits which are narrow, hairy siliques several centimeters in length. The upright pod is hairy, 65–150 mm (2+1⁄2–6 in) long, up to 3.5 millimeters wide and compressed from the back. The pods are wind spreaders.
This is a popular ornamental plant, widely cultivated for its abundant, fragrant flowers in spring. Many cultivars have been developed, in shades of yellow, orange, red, maroon, purple, brown, white and cream. It associates well in bedding schemes with other spring flowers such as tulips and forget-me-nots. It is usually grown as a biennial, sown one year to flower the next, and then discarded. This is partly because of its tendency to grow spindly and leggy during its second year, but more importantly its susceptibility to infections such as clubroot.
II. How to Grow and Care
Sunlight and Soil
Wallflower thrives in well-draining soil and full sun exposure, which are critical for its growth and flowering.
Watering
Adapted to the moderate climates of its native habitat, wallflower thrives with consistent moisture levels. This species exhibits a preference for well-drained soil and tolerates short periods of dryness, but it should be maintained with a balance of hydration to support its growth. Accordingly, wallflower benefits from watering every week. Typically cultivated outdoors due to its vibrant blossoms and growth habits, wallflower is especially notable for its flowering phase which requires careful water management to ensure robust blooms in response to seasonal rainfall patterns.
Fertilizing
For wallflower, a balanced fertilizer during the growing season supports robust growth, while high phosphorus formulas pre-bloom enhance flowering. Apply quarterly or per label instructions, adjusting for growth stage: vigorous feeding in spring and summer, reduced in fall, paused in winter. Measure precisely to prevent over-fertilization and root damage. Seasonal adjustments ensure wallflower maintains optimal health and vibrant blooms year-round.
Pruning
Wallflower benefits from regular deadheading to promote continuous blooming throughout its flowering season.
Propagation
A cherished favorite in gardens, wallflower thrives when propagated by cuttings. To achieve successful growth, select healthy, non-flowering shoots and remove the lower leaves. Dip the cut end in rooting hormone and plant in a well-draining potting mix. Ensuring the cuttings have warmth and moisture, but not waterlogged soil, will encourage root development. A semi-shaded spot is ideal to foster growth without scorching the delicate cuttings.
Transplanting
The prime time for nestling wallflower into their new homes falls between S1-S2, an optimal period when environmental conditions favor root establishment. A spot with abundant sunshine is preferred. Tenderly handling wallflower during transplanting can help avoid root shock, enhancing their chance of flourishing.
Repotting
Repotting wallflower, a compact bushy perennial, ideally in spring every 2-3 years to encourage robust health. Select a slightly larger pot to accommodate growth. Use well-draining soil and ensure the new container has adequate drainage holes. Post-repotting, water moderately and place in a sunny spot to recover. Provide extra care if leaves wilt, adjusting sunlight and watering as needed. This personalized care supports wallflower’s vibrant blooms.
III. Uses and Benefits
Wallflower is a compact, pretty flowering plant that is generally chosen as an ornamental by gardeners for its attractive blooms and long bloom time. It is also easy to care for, a plus to any gardener. It can fill beds and containers or can be mixed with other flowers. It is great in pollinator gardens as well.