How to grow wallflower
Overview
Wallflower (Erysimum cheiri) is a short-lived perennial in the Brassicaceae family, grown for its fragrant, colourful spring flowers and ability to fill gaps in garden beds. It thrives in cool to mild climates and requires full sun and excellent drainage to avoid root rot.
Varieties
- Erysimum cheiri 'Blood Red' — Deep crimson-red flowers, very popular in Australian cool-climate gardens.
- Erysimum cheiri 'Golden Bedder' — Bright golden-yellow, compact habit, excellent for mass planting.
- Erysimum cheiri 'Bowles Mauve' — Mauve-purple flowers, long-blooming and more perennial than typical wallflower.
Soil Preparation
Wallflower prefers a free-draining, slightly alkaline to neutral soil (pH 6.5–7.5). Improve heavy soils with coarse sand or gravel and incorporate lime if pH is too acidic. A thin layer of organic mulch helps retain moisture without causing sogginess.
Growing Guide
Plant wallflower in full sun with well-drained, slightly alkaline soil. Space plants 30–40 cm apart. Sow seed in late summer to early autumn for spring blooms, or transplant seedlings in autumn. Avoid heavy clay or waterlogged sites; raised beds or slopes work well. Pinch out tips after planting to encourage bushiness.
Sowing
Sow wallflower seed directly into the garden in late summer to early autumn, or into punnets for transplanting. Sow 3 mm deep, 30 cm apart, and keep moist until germination (7–14 days). Transplant when seedlings are 10–15 cm tall. Wallflower is easy from seed and often self-seeds.
Care
Feed with a balanced slow-release fertiliser in early spring as growth resumes. Deadhead spent flowers regularly to extend blooming. After the main spring flush, cut plants back hard (to 10–15 cm) to promote compact, bushy regrowth for a possible second autumn display.
Companion Planting
Wallflower pairs beautifully with spring bulbs like tulips, daffodils, and grape hyacinths, which share its bloom time and sun requirements. Avoid planting near water-hungry plants such as hydrangeas or ferns, as they will compete poorly with wallflower's need for dry conditions.
Common Pests & Risks
Aphids and caterpillars (especially white butterfly larvae) are common on wallflower in Australian gardens. Control aphids with a strong water spray or insecticidal soap; hand-pick caterpillars or use Bacillus thuringiensis (Bt). Powdery mildew may occur in humid, crowded conditions—ensure good air circulation and avoid overhead watering.
Troubleshooting
Yellow leaves: overwatering or poor drainage—reduce water and improve soil. Leggy growth: too much shade or insufficient pinching—move to full sun and pinch tips. Few flowers: lack of phosphorus or late planting—apply balanced fertiliser and plant in autumn. Powdery mildew: humid, crowded conditions—space plants and avoid overhead watering. Root rot: waterlogged soil—plant in raised beds or add gravel.