One of the most elegant spring flowering bulbs is Erythronium, with nodding flowers, reflexed petals and attractively mottled leaves. They are also one of the few plants that tolerate dry shade, though they do need more moisture during their growing season. Many of the species will spread well, thus covering shady or dappled areas under shrubs and trees beautifully.
The European dog's tooth violet, E. dens-canis, is even sturdy enough to naturalise in thin grass. Its curious common name refers to the shape of the bulbs, which resemble a dog's canine. They are yellow-white in colour and some of them produce offsets and stolons.
The genus is found in Europe, Asia and the USA, with the greatest diversity in the latter. The 20 species are classified as woodland or alpine. Those that grow naturally in woodlands have mottled leaves, bloom in the spring and are dormant in the summer. Those that grow in montane meadows have green leaves, summer flowers and are dormant in winter.
There are several woodland species commonly planted in the UK, including E. dens-canis, which produces pink to lilac flowers on short stems and has leaves mottled with pink and chocolate. Then there is E. californicum, with large creamy white flowers and mottled leaves. The popular variety 'White Beauty' is bred from this.
Another pretty species often used in cultivation is E. revolutum. Its flowers are in shades of pink much sought after and it has heavily mottled leaves. Two other dainty species are E. japonicum and E. hendersonii, which is arguably the most elegant of all Erythronium. Most people will have heard of the yellow-flowered 'Pagoda'. This is a beautiful hybrid between E. tuolumnense and E. californicum 'White Beauty'.
Erythronium are on the whole easy to grow, preferring a site in partial shade, in well-drained but moisture-retentive, soil. They are most at home planted in a woodland setting, under shrubs or trees. This provides ideal conditions - Erythronium like cool growing conditions in the spring with a period of drier dormancy in the shade in summer - and the larger plants take away any excess moisture in the summer.
The bulbs should be planted between August and October and will emerge the following April and May. The rule when planting or when dividing (which they do not like so avoid carrying out if possible) is to not let the bulbs dry out but to get them in the soil as soon as possible with some water.
WHAT THE SPECIALISTS SAY
JOHN AMAND, managing director, Jacques Amand Bulbs, Middlesex - "Erythronium are a superb bulb. They are just beautiful. I particularly like revolutum hybrids, the pink-flowered types for the garden. They are very good. Within those hybrids are some quite exciting crosses, including one we made that is named after my daughter Joanna. There is a limited supply of them, but we are working on making more available.
"One of the best - and one of my personal favourites - is E. californicum 'White Beauty'. It's extremely beautiful and increases very well. I also like E. japonicum. It's a stunning species. It has lilac flowers with purple markings in the middle.
"People like the varieties of the dwarf Erythronium, E. dens-canis, but the fact is that its newest hybrids are available in very limited amounts from a just a few nurseries in the country and they retail at around £7.50 a bulb.
"To understand the price differences it should be noted that a field-grown variety like 'White Beauty' is raised in tens of thousands, while a specialist nursery might offer 20-30 of an interesting new variety or species during the year."
NIGEL ROWLAND, owner, Long Acre Plants, Somerset - "The best pink is revolutum 'Knightshayes Pink'. 'White Beauty' is also a good doer. It always sells really well. The difficulty with more unusual varieties is that they take a long time from seed.
"Among them is E. hendersonii, which is very pretty and is popular as a result. You don't get commercial field production of the unusual varieties. They are raised and kept in containers. Erythronium are one of the most attractive of the spring flowering bulbs. Their colours tend to be quite unusual."
BOB WILLARD, general manager, De Jager Bulbs, Kent - "Sales of Erythronium are not massive, but they generate a lot of interest. We have around six varieties in our autumn catalogue. The lilac and pink varieties are most popular. Our hot seller at the moment is E. dens-canis 'Lilac Wonder', which has a lovely lilac pink flower with a chocolate brown basal spot.
"They do best in moist, retentive but well-drained ground. They multiply freely and are disease-free. They are robust bulbs and we only sell top-quality, top-size bulbs. Erythronium rarely fail."
SPECIES AND VARIETIES
E. albidum is a short, white form that flowers in March. Ideal as a woodland plant. Height: 10cm.
E. californicum Award of Garden Merit (AGM) (H4) is an excellent garden plant with large, pale cream flowers over well mottled foliage.
E. californicum 'Harvington Snowgoose' is a large, white-flowered form with heavily mottled foliage. Similar to 'White Beauty', but taller.
E. californicum 'White Beauty' AGM (H4) is considered to be the best of the whites for the garden. It is a vigorous variety that produces offsets freely, forming large clumps. Height: 20-25cm.
E. dens-canis is the European dog's tooth violet. It has shorter flower stems, reaching around 15cm high, bearing flowers from March to April that are usually pink to lilac, but sometimes white. Its green leaves are mottled with brown and purple.
E. dens-canis 'Lilac Wonder' has dainty flowers of lilac-pink with a chocolate brown basal spot. It is an early flowering variety, sometimes coming up in mid March. Height: 12cm.
E. dens-canis 'Purple King' flowers in April, producing broad petals of heather purple. Its foliage is marbled with chocolate brown. Height: 15cm.
E. dens-canis 'Rose Queen' has large, refined blooms of a delicate shade of clear pink. It is an excellent early-flowering variety that tends to increase rapidly.
E. dens-canis 'Snowflake' is a white-flowered form with mauve-purple anthers. It increases steadily.
E. grandiflorum has yellow flowers with either red, yellow or white anthers.
E. hendersonii is perhaps the most elegant of all Erythronium. It has lovely purple-pink flowers with a deeper marking in the centre. Height: 25cm.
E. japonicum is a charming species with violet-purple flowers and dark-purple anthers. Its flower stems are similar in height to those of E. dens-canis. Height: 15cm.
E. 'Joanna' is a lovely form with apricot flushed, pink flowers that change to pure pink. A mid season form.
E. oregonum is a species with heavily mottled foliage and white/yellow-centred flowers from the west coast of the USA.
E. 'Pagoda' AGM (H4) produces large plants with tall flower stems bearing three to four sulphur yellow flowers per stem in April. Very hardy and probably the easiest in the garden. Height: 25cm.
E. revolutum AGM (H4) is an elegant species that produces rose-pink flowers in April with a yellow centre and anthers. The leaves are heavily mottled bronze and green. Height: 15cm.
E. revolutum 'Knightshayes' produces pink reflexed flowers in March and April. The leaves are sometimes handsomely mottled in two-tone green and brown. Height: 15cm.
E. revolutum 'Knightshayes Pink' is an excellent flowering form. It flowers around two weeks earlier than the species and increases much more quickly.
E. tuolumnense AGM (H4) is a vigorous species from California. It bears two to three lovely bright yellow flowers on slender stems in April, above smooth, pale-green leaves that are uniform and unmottled.
E. tuolumnense 'Spindlestone' is a shorter, more compact and more floriferous form of E. toulumnense.
E. umbilicatum has small yellow flowers with a brown stripe on the outside of the petals and mottled leaves.