Plant profile: species hellebores Discover the delicate beauty of species hellebores
More understated than their hybridised cousins, these captivating and hugely variable plants lend the garden a delicacy and grace all of their own
When the pioneer hellebore breeders of the 1960s, Eric Smith and Jim Archibald, began the journey to the startling colours and forms that we have today, simple species played a crucial part. These plantsmen brought wild species together with each other and with existing selections and cultivars, such as ‘Black Knight’ from 19th-century breeders like Peter Barr, in a huge step towards creating the colours and colour combinations that are now so desirable. The pale greens of Helleborus odorus subsp. cyclophyllus, the purples, slate-blues and dark veins of H. torquatus, and the speckles of H. orientalis subsp. guttatus all played their part. Even some of the first double-flowered forms came from plants of H. torquatus collected in the wild.
The wild species that went into creating our modern cultivars are also fascinating to grow. The flowers are not large, and are often green and sometimes have a fragrance. But while these species were used by breeders, hellebore enthusiasts also began to collect wild species for their own refinement and, sometimes, prolific f lowering.
The native British H. viridis subsp. occidentalis, which grows in woodlands on alkaline clay, went into the early development of spotted, green-flowered forms. H. torquatus, famously discovered in 1929 by plantsman Walter Ingwersen while searching for privacy to accommodate digestive problems in the wilds of Serbia, was crucial in the development of dark-flowered forms. Two island species, H. lividus and H. argutifolius, helped bring us the finest foliage forms.
All are winter-flowering, most feature nodding, five-petalled, buttercupshaped flowers on stems that branch at the top, and all have divided foliage whose outer divisions are usually divided again (and perhaps again). Most, except the stemless species, produce flowering stems and leaves separately from the crown of the plant, and a few have foliage and flowers on the same stem.
The most intractable problem associated with hellebore species is their tendency to hybridise – it can be very difficult to keep them true to type. The flowers of all hellebores are adapted to cross-pollination, so if two compatible species are grown within bee-flight of each other, hybrids are guaranteed. While some species are vigorous, many can be slow to mature so it may take years for plants to reach a good size – with inevitable impact on their sale price; propagation by division is also very slow. The fact that many species look superficially rather similar to each other also creates difficulty, even for experts, exacerbated by the most recent reclassification that created new species.
With hellebore species as interesting as they are beautiful, which are most worth growing? The two island species, the hardy H. argutifolius, from Corfu, and the closely related but more tender H. lividus, from Majorca, should be high on the list, as they bring us structure, evergreen growth, good foliage and a long season of flowers. In its best forms, the hybrid between the two, H. x sternii, is exceptional.
The Christmas rose, H. niger, is always appealing, and recent selections flower reliably late in the year. H. foetidus is a fine garden plant with a wide distribution across Europe that has produced well over a dozen cultivars, all easy to grow and some very dramatic, but availability can be a challenge. The increasing flamboyance of single- and double-flowered H. x hybridus cultivars has distracted enthusiasts from the more demure species – and there currently isn’t demand.
Perhaps the most special of the species are those with purple or smoky colouring in the flowers. Helleborus atrorubens most often features purple-backed flowers with green interiors, and H. croaticus is similar. Helleborus torquatus also comes in smoky, slate-ish colouring, while H. purpurascens has larger, more rounded, flowers. Pink-flowered H. thibetanus is more eye-catching.
These wild species may not have the obvious impact of today’s garden hybrids, but those with a sense of history and an eye for detail will appreciate their role in the development of our favourite winter flowers and enjoy their quieter beauty. n
• Author Graham Rice is a garden writer and author of the RHS New Plants blog. His recommendations for the best species hellebores can be found over the next five pages.
Cultivation
Hellebore species vary in their needs. The stemless species are usually happy in good garden soil in at least some shade; the more open the situation, the more moisture they require. It pays to cut off the foliage of both evergreen and deciduous species in late autumn or early winter to prevent the carryover of disease. Thorough deadheading prevents the proliferation of unwanted hybrid seedlings. Mulching with weed-free organic matter in autumn helps maintain vigour and deter weeds.
Stemless species can be lifted and divided in September or October and either replanted at once or potted into 12cm pots and grown on for a year in a cold frame or a sheltered site outside before planting.
Helleborus foetidus and its cultivars are best in dappled shade or in a perennial border where taller, later-flowering plants provide summer shade.
Helleborus argutifolius is unexpectedly adaptable, but the tall stems often need support. The much smaller, closely related H. lividus appreciates frost protection, and thrives in terracotta pots in a cold greenhouse or sheltered porch. The hybrid between the two, H. x sternii, is a fine plant for winter containers, and some forms have exceptionally beautiful foliage as well as pretty flowers.
None of these tall-stemmed types are amenable to division and seed rarely comes true unless bees are excluded during flowering time. They may need support, especially in exposed situations; the flowering stems should be cut out at the base before the seeds are shed.
Hot, dry summers, along with protection from summer moisture and from winter frosts, are needed for the dramatic H. vesicarius. A large cloche is usually sufficient for this purpose. Plants can either be grown in the border or in a large pot in an unheated greenhouse.
Many forms can be propagated by seed, which should be sown promptly, as it ripens, in early summer. Seed needs a warm and moist period followed by cooling temperatures. Seedlings usually emerge in winter or early spring, but germination can be unpredictable. Seed-raised plants may take some years to flower.
Where to see and buy
• Ashwood Nurseries Ashwood Lower Lane, Kingswinford, West Midlands DY6 0AE.
Tel 01384 401996, ashwoodnurseries.com Ashwood Nurseries won a Gold Medal as well as The President’s Award for its hellebore exhibit at the 2018 RHS Chelsea Flower Show. The nursery runs hellebore tours in February, with an opportunity to purchase specially selected plants (check website for dates). • Hazles Cross Farm Nursery Hollins Lane, Kingsley, Staffordshire ST10 2EP.
Tel 01538 752669, hazlescrossfarm nursery.co.uk
Holds the National Collection of hellebores. This comprises all known species, with many forms of each on display.
• Kevock Garden Plants Lasswade, Midlothian EH18 1HX. Tel 0131 454 0660, kevockgarden.co.uk
Some potted plants are currently available, with dry bulbs and bare-root plants on sale later in the year for delivery in October.
Species hellebores can be difficult to get hold of and stock is often limited, but it is often worth contacting nurseries with your requests as this can fuel demand and encourage growers.