Discover a National Plant Collection of heather at RHS Garden Wisley

Much like the evolving trends of garden fashions, the National Plant Collection of heather has taken many forms at RHS Wisley. For its first introduction to Howard’s Field in 1987, the collection was showcased within island beds with a backdrop of dwarf conifers and finely manicured lawns. In 2017, however, Mark Tuson and the Welcome and Riverside team at RHS Wisley took inspiration from the rolling landscapes of natural heathlands to create the Heather Landscape that can be seen today.

The sandy, acidic soil makes the Heather Landscape a challenging area to garden, however many heather species are adapted to these harsh conditions and thrive against the odds. Densely planted drifts of Erica, Calluna, and Daboecia create flowing swathes of pinks, purples and whites, which are boldly contrasted by the striking shapes of Yucca rostrata and Verbascum thapsus. Drought-tolerant, vibrant

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

© Eloise Sutton, 2025

The National Plant Collection of heather in the Heather Landscape at RHS Wisley

Erica

Erica in the wild

Frequent explorers of the English countryside are almost certain to have come across at least one of the four

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

Is there an Erica for every gardener?

Unbelievably, there is almost always an Erica in flower in the Heather Landscape at RHS Wisley. While the summer-flowering species are impressive, it’s the species that display a profusion of flowers during the bleakest of winter months that excite me the most. Whether that be the towering columns of tree heathers, or the carpeting mounds of Erica carnea, it is a real treat to witness the annual nectar feast provided for insects as they are just waking up for the year. The deafening buzz of satisfied insects on a cold, sunny day in March really does awaken my spirit for the

The period of time when an individual plant is in active growth. This will depend on the local climate and light levels, and can vary between different plants, although it is broadly from spring to autumn.

Erica: Tree heathers

It surprises me that tree heathers are a rare sight in gardens. These large, evergreen shrubs (not trees, as their name would strongly suggest) grow with an upright, softly branching habit and are blanketed in flowers anywhere between autumn and spring, depending on the species. Best grown in full sun and acidic soil, these shrubs make the perfect wildlife-friendly backdrop to any planting scheme, especially in the south of England where winters are less harsh (tree heathers may struggle in areas that experience prolonged and intense frosts).

Unlike most other species of heather, tree heathers will happily tolerate regenerative pruning. It is best to gently prune tree heathers into their desired shape when they are young, then leave them be, but suffering or unsightly plants can be harshly pruned to revive their strength. A stroll through the Heather Landscape in late winter will reveal the magic of tree heathers, where the flowering clouds of Erica arborea, Erica lusitanica AGM and Erica × veitchii are standout features. The most surprising of all, perhaps, being the 3m tall Erica platycodon which dwarfs the 30cm mounds of Erica carnea that flower nearby. It is hard to believe that these are the same genus.

© Eloise Sutton, 2025

Erica x veitchii is a hybrid between Erica arborea and Erica lusitanica. Surprisingly, this tree heath it is tolerant of alkaline soils. Erica x veitchii ‘Gold Tips’ (shown here) is a favourite of mine as its blanket of flowers almost twinkle in sunlight

Three species for winter colour

These three species are easily distinguishable by their growth habits: Erica carnea forms a low-growing carpet, Erica erigena is taller and bushy with some cultivars reaching a height of 4ft, and Erica x darleyensis, a

A plant produced by crossing two distinct parents, often different species, to produce offspring that combine the characteristics of both. Hybrids can occur naturally, but crosses are often made deliberately by plant breeders to produce plants with better yield, improved flowering or vigour, or improved disease resistance.

Erica erigena is perhaps my favourite species of Erica. I enjoy how much their tall, bushy forms juxtapose the common stereotype of ‘old-fashioned’ carpeting heathers.

Unlike all other heathers, these winter-flowering species are tolerant of a much wider variety of growing conditions and soil types. This arguably makes them the most relevant for the everyday gardener. For those wondering if they can grow heathers without the acidic, free draining soil that is usually required, give one of these species a try.

Summer-flowering Erica are beginning to struggle here in the South-East. Their shallow roots make them very vulnerable to extremes of climatic conditions, including the abnormally hot and dry summers we are now experiencing in Surrey. This is worrying for our natural heathlands, as all native Erica are summer-flowering. If you are growing summer-flowering Erica in your garden, ensure your growing conditions are suitable for the species you select.

© Eloise Sutton, 2025

Erica x darleyensis ‘Arthur Johnson’ has particularly long flowering spikes, presenting columns of light pink in airy sprays. The length of the flowering spikes makes this a useful cultivar for floristry

© Eloise Sutton, 2025

Erica vagans ‘Viridiflora’. The feathery lateral shoots borne after flowering bring unique interest to this cultivar

Calluna vulgaris

An all-rounder for wildlife

Calluna vulgaris is the dominant heather that you might see thriving on a heathland, moorland, or bog where it grows unrestricted by the acidic and infertile conditions. The self-seeding nature of the uncultivated species allows it to quickly colonise a heathland as it fills every crack and crevice nature provides. The scale-like, overlapping leaves distinguish Calluna vulgaris from the needle-like leaves of Erica, the other heather genus commonly found in UK landscapes. Differing also in flower form, Calluna vulgaris has dense racemes of urn-shaped flowers that are more accessible to pollinators than the tightly arranged flowers of Erica, providing an invaluable nectar source for pollinators into late summer. This precious nectar source is more than just food, too – researchers have discovered that a compound found within the nectar of Calluna vulgaris, aptly called callunene, protects bumblebees from the fatal parasite Crithidia bombi. Flowers truly are medicine.

It is not just pollinators that benefit from healthy habitats of Calluna vulgaris, however. The mosaic of niches created by established colonies of Calluna vulgaris across heathlands – including a mix of bare ground, foliage cover and older, sparser growth – provide basking areas for reptiles and safe nesting sites for solitary bees, wasps and birds. Pockets of moist shade provide the perfect habitat for mosses, lichen and fungi while beetles, bugs, butterfly and moth larvae eat the plant for essential nutrients. Next time you walk through a heathland, imagine it as a miniature forest for insects and small mammals alike.

The risk climate change poses to the health of our heathlands, the heathers in your garden, and the wildlife that depend on them cannot be overlooked. One example is the changing impact that the heather beetle, Lochmaea suturalis, is having on heathland heath. This native beetle can defoliate large areas of heather when outbreaks occur, an event that is becoming more common as our climate warms. Our cold winters and cooler springs used to help keep egg populations of this beetle small, however warming seasons are throwing these populations out of balance increasing the risk the beetle poses to our heathlands.

Calluna vulgaris (Garden Girls Series) with Calluna vulgaris ‘Underwoodii’, Calluna vulgaris ‘Marleen’ and Yucca gloriosa ‘Variegata’ in the Heather Landscape at RHS Garden Wisley

Growing Calluna in your garden

Although gardeners may not have the right conditions, resources or desire to grow Calluna vulgaris on the scale of the National Plant Collection of heather at RHS Wisley, this is not to say that including a small pocket of the species within your beds will not bring huge benefits for the wildlife in your garden. Calluna vulgaris is the perfect companion for acidic soils in full sun, where a light, annual clipping of its foliage will help keep a compact habit (don’t be shy, Calluna vulgaris was once a preferred food for grazing livestock!). If you have a heavy or alkaline soil, try adding horticultural grit and use an ericaceous mulch, or grow in a well-drained pot with ericaceous compost.

For those who do not enjoy the bold and contrasting palettes that Calluna cultivars are perhaps known for, the softer, more subtle cultivars may be more preferred. Calluna vulgaris ‘Johnson’s Variety’ provides the Heather Landscape with sprays of lilac flowers in airy racemes throughout late summer, and the silvery mauve carpets of ‘Jan Dekker’ rival even the most loved lavenders. A stroll through the Heather Landscape at RHS Wisley from early to late summer may just reveal a new favourite to the most unexpecting eye.

Calluna vulgaris ‘Wickwar Flame’ is among the many colour-changing cultivars that will please the most adventurous of gardeners. Mauve flowers are held above contrasting gold foliage, which turns neon shades of orange and red when fully exposed to winter cold. It’s not a personal favourite, but I appreciate its boldness.

Attention must also be paid to the Garden Girls Series of Calluna vulgaris. Bred with the intention of extending their season of interest well into the autumn, these cultivars are ‘bud bloomers’ whose

A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

bud

Daboecia

Daboecia × scotica ‘Sarah’

Daboecia in the wild

The genus derives its name from the Irish description of the plant, St. Daboec’s heath. The most widely distributed species of the genus, D. cantabrica, is native to the coastal regions of western Europe and the Connemara region of Ireland where it can still be found growing today. The native range of this species give an indication of its growing requirements – the plant may struggle in frosts but will tolerate exposed, windy and salty conditions. Like all heather genera, acidic soil and full sun make for ideal growing conditions.

Daboecia azorica, native to the Azores, is the second species in the genus but it is not currently in cultivation. D. azorica and D. cantabrica accidentally hybridised in cultivation however, to produce a hybrid that has become a successful garden plant - Daboecia x scotica. The leaves of D. x scotica are smaller than those of D. cantabrica, making it more successful as weed-supressing ground cover. D. x scotica ‘Ben’ is an extreme example of this, producing minuscule leaves in a very tight mound. D. x scotica is also observed to flower earlier than the straight species. The National Plant Collection of heather begins to see the first of the Daboecia x scotica flowers in May, whereas the straight species waits until June.

Daboecia cantabrica ‘Romantic Muxoll’

Daboecia in the garden

Flower colour of Daboecia ranges from white to red, with many pinks and purples being observed in-between. Most cultivars present a delicate, nodding flower, however D. cantabrica ‘Pink Blum’, ‘Purple Blum’ and ‘Pinky Perky’ orient their flowers towards the sky. D. cantabrica ‘Romantic Muxoll’ and ‘Charles Nelson’ are the few double-flowered cultivars, however the difference is best observed up close. ‘Charles Nelson’, a variation found in Galway, interestingly produces single flowers at the start of the season and transitions into

A type of flower that has extra petals, often having a fuller appearance. Plants with double flowers are often considered more ornamental and showy than those with single flowers, though they are generally not as good for wildlife, having little or no pollen. Some plants naturally produce double flowers, while others may be bred for this trait. Examples of plants with double flowers include roses, sunflowers, dahlias, and zinnias.