If a planting scheme calls for year-round colour, specifiers will do well to add Corylopsis to their design to plug the gap between winter-flowering Hamamelis and spring-flowering Forsythia and Prunus.
This increasingly popular genus of around 20 species is part of the witch hazel family, Hamamelidaceae. All are slow-growing deciduous shrubs or small trees, with toothed leaves and racemes of small, bell-shaped and often fragrant flowers, offering vibrant colour on bare stems in early spring.
The genus is similar to Forsythia in that yellow flowers appear before foliage, but Corylopsis offers a more elegant form, with the different plant sizes found across the genus, making them suitable for a variety of planting styles and locations.
The popular C. pauciflora rarely grows above 1.5m and in many cases remains at 60cm, acting as a vibrant background for spring bulb schemes. Its small size lends it to container and border plantings. Its common name, buttercup hazel, derives from its profuse pastel or buttery-yellow blossoms.
Misleadingly, ‘pauciflora’ means ‘few flowers’ but this refers to the lack of blooms per cluster, which occur profusely along the whole branch. The early spring blooms give way to rounded, veined, tooth-edged leaves typical of hazels, which in spring are fringed in reddish-purple, fading to green as they age into summer.
One of the largest and hardiest forms, C. glabrescens, can grow to 5m in height, and when pruned as a multi-stem, makes an ideal frame for summer-blooming climbers as well as a centrepiece for an early spring display. The unusual C. willmottiae ‘Spring Purple’ offers extra spring colour with its purple foliage.
Although the golden yellows and browns of Corylopsis’ autumn leaves have a visual appeal if they remain on the plant long enough, this is most likely with C. glabrescens var. gotoana and C. spicata.
Preferring an acid soil, Corylopsis does well when mixed with ericaceous plants such as Rhododendron, Azalea and Pieris — its deciduous habit creating breaks in the dense foliage. Care should be taken in the first few seasons after planting as a late frost will often cause die-back even after flowering, although a sheltered site can prevent this. The plants also dislike extreme summer temperatures and a shaded location is advised, particularly if there is to be no irrigation or regular watering.
What the specialists say
Steven Dance, office manager, Burncoose Nurseries, Cornwall
“C. pauciflora is our most popular seller. It’s not too intrusive, remains small and sits well in a small space. C. willmottiae and C. sinensis var. calvescens are also popular choices.
“They are all lovely shrubs to have in the garden, particularly from February to March, when it’s nice to have something of colour in planting displays. If you’re looking for year-round colour, Corylopsis will form part of a good colour scheme. They do prefer acid soil. We find they perform well in both sun and shade but we advise they are kept out of any cold, easterly winds as they can be a little tender.”
Dr Peter Dykes, National Collection Holder, Chadwich Manor, Worcestershire
“All species flower before they come into leaf around mid-March, before the showy cherry trees, offering colour when there is little else. Plants in the genus are very similar, however. I have around 15 samples and I’m still only clear of the origin of five of them.
“The common C. pauciflora is a very reliable species and is offered by most plant dealers, although it normally doesn’t grow above 60cm high. C. spicata is a nice medium-size shrub and the flowers offer interesting red stamens. C. veitchiana can reach as high as 6m.
“The shrubs are frost sensitive at the point when the sap is rising. I’ve lost a fair number just after flowering when a late frost has taken hold. Fortunately, we haven’t had many of those in recent years thanks to warmer winters, but people in the South will find them easier to grow than those in the North. I protect mine with fleece just after flowering to safeguard the collection.”
David Domoney, garden designer, Kineton, Warwickshire
“Anything that bears catkins like those found on Corylopsis adds a degree of animation to a garden or planting scheme; their movement in the breeze brings an added dimension to the garden. There are a lot of plants that are overlooked for early in the season, with most colour coming from evergreen, variegated plants and the stems of dogwoods and Salix.
“Catkins aren’t found on many plants and their colour and architectural quality make them a firm favourite in garden design. An additional benefit is that they are food for birds in difficult months, so they’re great for bringing wildlife into the garden for early season feeding.”
Species and cultivars
• C. glabrescens var. gotoana is a hardy species that will tolerate alkaline soil if drainage is good. The largest-leaved variety in the species with blue-green foliage, it also has better autumn colour than others in the genus.
• C. glabrescens var. gotoana ‘Chollipo’ is similar to Corylopsis glabrescens var. gotoana, but with added silvery-white on underside of leaves.
• C. pauciflora, the buttercup hazel, is the smallest Corylopsis, growing no more than 1.5m and often wider than it is tall. Small leaves appear bronze when young. Also earliest to flower compared to other Corylopsis, bearing large, fragrant, buttercup-yellow blooms.
• C. willmottiae, the Willmott winter hazel, is an open to rounded species growing to 4m in height. Flowers are green-yellow.
• C. willmottiae ‘Spring Purple’ is similar to C. willmottiae but with attractive young purple foliage.
• C. spicata is a vigorous species, reaching 3m in height, with distinctively rounded, almost heart-shaped leaves. Flowers are also distinct from other Corylopsis, bearing red stamens. Better autumn colour than some varieties.
• C. veitchiana is an easy to grow variety, performing well on heavy, clay soils. Long leaves are often purple when young and its primrose-yellow flowers offer a sweet fragrance.
• C. veitchiana ‘Purple Selection’ is a purple-leaved variety, not as vivid as C. willmottiae ‘Spring Purple’, but more upright in habit and a stronger performer.
• C. sinensis var. calvescens is a strong-scented variety growing to 3m.