Some plants are such good value and so dependable that it’s difficult not to be evangelical about them. Perennial wallflowers (Erysimum) fall into that category. Some start to flower in February or March, and in mild years they may still be going at Christmas. Not bad, eh?
Technically, there are two types of erysimum, perennial and biennial. Experimentation has shown that if you leave biennial wallflowers (shorter, about 15cm, grown from seed and formerly called Cheiranthus, but now thankfully erysimums too) in the ground they often come back for a few years, forming small evergreen bushy plants. The reliably perennial, larger erysimums (about 40-60cm), which I’m focusing on, are longer flowering and more impactful. They do best in a sunny sheltered spot — and in colder areas may need fleecing in winter — but otherwise are extremely easy to care for.
Perennial erysimums’ upright blooms come in a range of vibrant flower colours, from deep mauves and purples, through yellows and pastel pinks, to spicier oranges and reds. ‘Bowles’s Mauve’ is an outstanding performer, a single colour throughout, whereas many have jolly bicoloured (two-tone) flowers. ‘Winter Sorbet’ (it flowers from around March to July, so should be named ‘Winter, Spring and Summer Sorbet’, but that would be a long plant label) is the latter. Carrying orange flowers with deep smoky purple tints as they age, they are ideal for jazzing up a pot or border. All erysimums make fine cut flowers for a vase (setting off narcissi and tulips beautifully) and will last longer if the freshly cut stems are seared in boiling water for about 20 seconds.
Erysimums are great for pollinators, providing important nectar and pollen for early bees, and will be regularly visited throughout the season — another fine reason to get enthusiastic about this rather humble plant.
Growing tips
The loose term “wallflowers” (found seeded and growing in walls) gives an indication of the conditions they enjoy. They like plenty of sun and a well-drained neutral to alkaline soil that isn’t too rich. An overly rich soil will result in plenty of leaves, but reduced flowering. Add plenty of grit when planting to improve drainage if necessary, or plant in a container in a free-draining soil-based compost. Protect plants with a cloche during harsh frosts.
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Erysimums can get a little leggy if left to their own devices, so trim them when flowers fade to keep a compact shape and encourage more blooms.
How to take cuttings
Perennial varieties are easy to propagate through cuttings. Some prunings can make ideal cutting material (taken around early to mid-July) and are a fine way to keep your stock going when the old ones die out. Look for shoots that are about 10cm long — if they have flower buds on, remove them. Trim under the node, remove the lower leaves and plant into small pots of gritty compost with their top leaves showing and keep moist. Pot up if rooted around early September or leave them in a very sheltered spot or cold frame until next April, then plant out.
Joe’s favourites
‘Golden Jubilee’
Fresh bright green foliage and golden yellow flowers fading to a softer lemony yellow. Height 20cm x spread 40cm.
‘Winter Sorbet’
Burnt orange and purple flowers. Height 40cm x spread 50cm.
‘Winter Orchid’
Scented. Coppery orange flowers turning to purple as they fade. Height 40cm x spread 30cm.
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‘Apricot Delight’
Cheery apricot orange flowers for a bit of zing. Height 50cm x spread 50cm.
‘Winter Light’
Bright yellow flowers. Height 30cm x spread 45cm.
‘Bowles’s Mauve’
Hugely popular for good reason. Deep mauve flowers on an upright bushy plant. Height 75cm x spread 60cm.
‘Butterscotch’
Fragrant and compact with yellow and peach coloured flowers. Height 30cm x spread 60cm.
‘Gogh’s Gold’
Shades of amber to orange and pale yellow, fading to soft pink. Height 35cm x spread 40cm.
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‘Constant Cheer’
Brick-red flowers that fade to purple. Height 45cm x spread 60cm.
