Wallflowers are plants with both a good garden appearance and a bouquet

Press, 11 October 1979, Page 15

Wallflowers are plants with both a good garden appearance and a bouquet

GARDENER’S DIARY

Derrick Rooney

Wallflowers are not only nice to look at in the garden, they are nice to pick and sniff, too, as their pig-Greek botanical name tells us: Cbeiranthus cheiri. The great Linnaeus, Swedish botanist of the 18th century who invented the modern binomial system of plant naming, let his scholarship slip when he gave this mouthful to the wallflower. “Cheiranthus” is an interracial composite of the Greek “anthos,” meaning flower, and an Arabic word, “kheyri,” meaning sweet-smelling. The “cheiri” bit is also Greek, and means hand — so a loose Anglicisation of the

wallflower's botanical name is “sweet-smelling flower for hand bouquets.” The English name, “wallflower.” has become synonymous with shy and blushing virginity, but for once the obvious explanation of its provenance is the correct one: the wallflower is not a native of Britain, but where it has escaped from gardens and naturalised in the milder clima'tes, it loves to grow in old walls. So the English call it “wallflower.” Wallflowers are treated as annuals in the seed trade, but they are really short-lived sub-shrubs, or shrubby perennials; they grow well for two or three years, but unless heavily

and regularly pruned they lose vigour and die back. They come with flowers in various shades of yellow, red and brownish orange, either as mixtures or as separate colours. The hybrids with the

shrubby Cheiranthus mutabilis (grouped under the name Cheiranthus “Kewensis”) do not come true from seed, but most of the wild forms do, and if grown in isolation the

separate colour strains can be maintained for quite a long time: one, in my garden, is in its third generation from home-saved seed, and so far has changed neither character nor colour. It is called, for inscrutable British reasons, “Ivory White,” though there is no trace of either ivory or white in it; the leaves are rich green and the flowers open primrose yellow, and fade to cream. Their scent, too, has a different air to it, and is readily distinguished from that of the persistent old wild wallflowers, in single and double forms, that come up year after year in a narrow border against one wall of our house (the border has been remade twice, and the original wallflowers were scrapped years ago, but still seedlings come up) — an indication perhaps of hybridity with one of the nine or 10 other species of cheiranthus. or with the so-called “Siberian wallflower,” w-hich is neither Siberian nor a wallflower, but is a “hybrid species” belonging to the closely related genus of erysimums. or “blister cresses.” All seed merchants and most popular gardening books list Siberian wallflowers under the name "Cheiranthus allioni,” and it was under this name that the strain received an award of garden merit from the Royal Horticultural Society after trials at Wisley Gardens in 1927. But it should really be called “Erysimum X marshallii,” the “X” being an international symbol denoting hybridity.

Like the other wallflowers, Siberian wallflowers are perennial, but they flower so freely that they exhaust themselves in a season, and are usually treated as biennials — i.e., plants that spend their first year growing, their second flowering, and then die,” The source of the orange pigment is a lanky Caucasian annual. Erysimum perofskianum. The other parent is Erysimum ochroleucum. a sprawling perennial from the Jura mountains on the Franco-Swiss border. Siberian wallflowers, being of modest height and bushy, are exactly halfway between the parents. The history of this popular garden flower is somewhat confused, and the plot is thickened, or perhaps just stirred up, by the fact that tile name “Marshallii” has also been given in recent years to an orange-flowered “perennial” hybrid of Cheiranthus chifi. But one fact is beyond dispute: Siberian wallflowers have been brightening gardens for more than a century.

They seem to have originated by one of those happy, bumbling accidents that prove, occasionally, not only that ignorance is bliss but that it is useful, too. An article by one Joseph Harrison, a flower grower of Downham Market. in the 1850 “Floricultural Cabinet” told the story straight from the horse’s mouth. Harrison had the plants flowering in his borders in May, 1850. having received the seed from a Mr John Marshall, of Limburn. Marshall, as Harrison told the story, had had difficulty obtaining seed from a'plant of Erysimum ochroieucum in his garden — so he pollinated its. flowers with pollen from E. perofskianum! The seed thus obtained was sown in the open border in 1846, and a year later the plants bloomed. One had pate yellow flowers, and was rejected. but tiie others were orange, and were saved. Harrison wrote that the plant was "easily propagated,” but he did not say whether by seed or cuttings. However, by the 1920 s the seed strain was firmly fixed, and in a note in the R.H.S. journal announcing the award of garden merit F. J. Chittendon observed: “It is so free in flowering that it may flower itself to death, and it is therefore well to treat it like a wallflower, sowing the seed in June for flowering the next early summer, and it comes true from seed.” What separates the erysimums from the “true" wallflowers? Very little. There are about 80 species of erysimum, in both the Old World and the New (whereas cheiranthus is confined to the Canary Island and Asia Minor), and most of the erysimums occur in the alpine or subalpine regions (cheiranthus does go up to 7000 ft in the Canary Islands). But the only obvious distinguishing feature to the layeye is that the seeds of erysimums are in single rows in the pods, whereas cheiranthus seeds are in two rows. The two families interbreed readily, and spontaneous intergeneric hybrids are likely to occur wherever the two are grown side by side. One of these, a bushy perennial with amber flowers turning red as they age, is seldom seen in nurseries, but quite a few gardens have it because it strikes readily from cuttings.

It is not long lived, and has to be renewed frequently, but is worth the effort because its flowers are such a striking colour. I believe it is called “Miss King’s” or “Newark Park Variety.”