How To Grow Wonderful Wallflowers
Wallflowers create a vibrant, highly scented spring display
Biennial wallflowers (Erysimum cheiri) are wonderful for a spring display; easy to grow and smell delicious. Although classed as biennials they are in fact short-lived perennials, but you get a better display if they are replaced every year. The biennials are native to Europe, thriving in poor dry soil, often in wall crevices, hence the name. Their early flowers are a good source of nectar for early flying insects. They are a member of the cabbage family and as such are susceptible to the pests and diseases which usually attack the brassicas. They come in a range of colours: reds, yellow, orange, purple, white, bronze and bi-colours, so there is a colour for every planting scheme. As biennials they germinate, develop foliage and grow roots in the first year, stay dormant over winter then flower in the following spring. They can be sown as seed or bought as plants in the autumn, either as bundles of bare-root plants or as a bedding pack where they are potted up singly.
They need a very well-drained sunny site; if your soil is a little bit heavy dig in some horticultural grit to improve the drainage. They need an alkaline soil so apply a dressing of lime. Don’t improve the soil; they need it poor otherwise they put on too much soft growth which is liable to get frosted in the winter. They are traditionally planted with forget-me-nots and tulips; plant before the tulips to avoid damaging the tulip bulbs.
Sowing seed and planting
Sow seed in April for flowering the following March/April. Sow in a peat-free seed compost, keep just damp. When they have germinated and formed two pairs if leaves prick out into a well-raked bed to grow on. Plant approximately 10cm (4”) apart in rows 10cm (4”) apart. Plant into their final flowering position in autumn. Pinch out the growing tip in autumn to make a bushy plant.
Make sure they receive sufficient water during dry spells. Do not fertilise. Throw on the compost heap when they have finished flowering.
Pests and diseases
Clubroot is a fungal disease which causes the roots to swell and become distorted. It can turn the foliage a purplish colour and severely retards growth. There is no chemical control; liming the soil helps lessen the effect of the fungus. Destroy any infected plants, don’t put them on the compost heap.
Cabbage root fly larvae eat the roots and cause the plant to wilt and die. Brassica collars can be used to stop the larvae crawling down to the roots. There is an organic nematode control available, but as yet there is no chemical control available to amateur gardeners.
Recommended seed varieties:
Fire King – height 45cm (18”); deep scarlet
Cloth of Gold – height 45cm (18”); strong yellow
Canary – height 15 – 20cm (6 – 9”); yellow, dwarf
Tequila Sunrise – 25 – 30cm (10 – 12”); mix of reds, purple, orange and yellow