The Indomitable Ivy: Drought, Resilience and the Quiet Power of Hedera
By Katya Lebedev , Cultivar Registrar, Royal Horticultural Society
As cultivar registrar for the RHS and an avid collector and close observer of the Hedera genus, I have spent two full years in the company of the largest collection of ivy in the world — cataloguing its extraordinary diversity, marvelling at the ingenuity of its forms, observing its mutations (and attempting to channel them somewhat), all the while advocating for a plant that the gardening world has too often taken for granted. Yet even for a devoted Hedera enthusiast like myself, there are moments that prompt genuine astonishment. This past week was one of them.
Five days. Forty degrees and above. And my ivies — planted in open ground since the beginning of autumn — stood firm without flinching, without wilting, without a single leaf lost to the scorching heat. The display was not merely survival; it was something closer to panache.
The Woodland Plant That Forgot Its Limits
There is a reasonable assumption, held by many gardeners and myself at the beginning, that ivy is fundamentally a plant of cool, damp shade. Hedera helix, after all, is native to the woodland floors and rocky hillsides of Europe, from Spain in the south to Norway in the north — a plant accustomed to the dappled light of a forest canopy and the moisture retained by its leafy, humus-full understory. It seems, on the face of it, an unlikely candidate for heat heroics. It's no rosemary, no thyme - optimised for the scorchers with small leaves and powerful root systems.
And yet.
Once established in open ground, ivy reveals a resilience that confounds expectation. It will tolerate not only the absence of water but also the secondary hardships that drought brings with it: compacted soils, sharp temperature fluctuations, and relentless sun. The key lies in that establishment — and here, autumn planting proves its worth. A plant set into the ground in early autumn has the gentler months of winter and early spring in which to extend its roots quietly and purposefully before summer arrives. By the time a heatwave comes calling, those roots have found their footing.
Three Cultivars in the Crucible
My collection includes a wonderful breadth of Hedera forms, but three cultivars in particular have been the focus of my attention this week as the thermometer pushed into territory that would have daunted a hardier-seeming plant.
'Parsley Crested' (H. helix 'Parsley Crested', also known as 'Cristata')
One of the most delightfully ornamental of all ivies, and a plant I hold in particular affection for its ruffles and frills - so wonderfully extravagant even when she could be plain. Her leaves are broad and almost circular, with wavy, ruffled margins that give them the crinkled appearance of flat-leaf parsley — hence the name :) . In milder seasons the foliage is a fresh, well-veined mid-green; come winter, the stems and veins flush a superb copper-red that makes the plant seem newly lit from within. Granted an Award of Garden Merit by the RHS in 2002, it has been in cultivation since the 1950s in the United States and remains one of the more vigorous and adaptable of the ornamental forms, usable equally as a ground cover or a modest climber to around two metres. Through five days of searing heat it has not so much as curled a leaf though the coloring has veered from mid-green to a chartreuse green/yellow. We'll continue watching to see what happens next as we aren't even in the middle of summer.
A cultivar of a rather different character — more sharply graphic in its effect. Its five-lobed, arrowhead-shaped leaves carry a distinctive central macule of light green to yellow-green, lending the foliage a faintly luminous quality that earns the cultivar its name. It originated as a sport, discovered in 1980 by Ken Frieling of Glasshouse Works in Ohio, and is a highly branched variety producing exceptionally dense, layered foliage. The colour is at its most vivid in cooler, richer soils, and even under this week's relentless sun the characteristic variegation has held, if in a subtler register.
This is the odd one out in any collection, and I mean that affectionately. Unlike its climbing and trailing relatives, 'Erecta' has transitioned into its adult, arborescent form — a non-climbing, upright, shrubby ivy that stands independently without need of support. It is a botanical curiosity as much as an ornamental one, occupying a space in the border that one might otherwise give to a compact evergreen shrub. In its juvenile context on the woodland floor it would have been a spreader; in this fixed, matured form it is a study in composed self-sufficiency — and through this heatwave, utterly unruffled.
Roots in the Ground, Roots in the Earth
The secret to the performance of these plants lies, in no small part, in the manner of their planting. These are specimens placed directly into open earth — not containers, not raised beds with their more rapid moisture loss, but proper ground, with all the thermal mass and residual moisture retention that entails. And planted in early autumn, when the soil is still warm enough to encourage immediate root extension but the air cool enough to reduce transpiration stress. By the following summer, such plants are genuinely, rather than theoretically, established.
This is a point worth making clearly for anyone tempted to dismiss ivy as a plant that merely tolerates. 'Parsley Crested', 'Tiger's Eye', 'Erecta' — these are not passive survivors. They are plants with a deep biological repertoire that includes the ability to withstand atmospheric drought, poor soils, compacted ground, and temperature extremes that would distress many more pampered garden plants.
The Power of Ivy: An Ecological Argument
To admire Hedera only for its drought tolerance would be to shortchange it considerably. Ivy is, in ecological terms, one of the most significant plants a gardener can grow.
Our nursery and experimental garden is situated in the Deux-Sèvres within Nouvelle-Aquitaine, one of France's most biodiverse regions for pollinators. The mosaic of bocage, meadows, wetlands and the vast Marais Poitevin - makes it genuinely exceptional territory for insect life.
The broader picture
France has initiated a National Plan for Pollinators alongside a French Red List of Bees and Hoverflies, reflecting just how significant and threatened this world is. Wild pollinators in France include approximately 1,000 species of bees alone, along with many other taxonomic groups - butterflies, hoverflies, hawkmoths, wasps, beetles, and more. Deux-Sèvres sits right in the heart of this richness.
The bocage and its corridors
The hedgerow landscape - the bocage - that still characterises much of Deux-Sèvres is critical. Butterflies, dragonflies, wild bees, and beetles play a fundamental role in pollination, soil fertility, and the feeding of many birds throughout the Poitou-Charentes region, though some species that were once common are now becoming increasingly rare. The bocage hedges serve as ecological corridors that allow species to move freely between habitats — and their loss to agricultural intensification is one of the region's biggest threats to pollinator diversity.
The bees
France has around 1,000 wild bee species beyond the honeybee, and western France harbours a strong community of them. You will be familiar with the large, deep-voiced violet carpenter bee (Xylocopa violacea), a dramatic insect that is very much at home across this part of France. Among bumblebees, species like Bombus terrestris, B. lapidarius (the red-tailed bumblebee) and B. pratorum (the early bumblebee) are characteristic of the region. Then there is an extraordinary world of solitary bees — mining bees (Andrena spp.), mason bees (Osmia spp.), leafcutter bees (Megachile spp.), and wool carder bees — many nesting in bare soil or hollow stems and often invisible to the casual eye but doing enormous pollinating work.
The ivy mining bee (Colletes hederae) - a specialist companion of Hedera - is spreading northward and westward across France and is now well established in the region, timing its entire flight period to coincide with ivy's late-season flowering. It is one of the most direct and tangible links between your collection and the wider pollinator community.
The Marais Poitevin — a pollinator stronghold
The Marais Poitevin, which stretches through Deux-Sèvres toward the coast, is one of the great wildlife habitats of western France. The nature reserve holds over 250 bird species, 40 fish species, 60 species of dragonflies, and 80 butterfly species. It received RAMSAR certification in December 2023 in recognition of the conservation work being done to preserve its natural environments and biodiversity.
References:
Butterflies
The butterfly fauna of Deux-Sèvres is particularly rich. Among the more notable and protected species present in the region are :
marsh fritillary (Euphydryas aurinia), which depends on wet meadows with devil's-bit scabious
the scarce copper (Lycaena virgaureae)
and the large copper (Lycaena dispar — Cuivré des marais in French), a spectacular wetland butterfly strongly associated with the Marais Poitevin and protected under the EU Habitats Directive.
The purple emperor (Apatura iris) haunts the woodland edges, and on warm summer days species like the silver-washed fritillary, white admiral, painted lady, red admiral, and various blues and skippers are all regular presences across the bocage and meadow habitats.
Hoverflies and other pollinators
Hoverflies (Syrphidae) are the great unsung pollinators of western France — often bee-mimics in appearance, they visit flowers in huge numbers and are especially important for many wild plants. The drone fly (Eristalis tenax) is among the most common and widespread. Ivy is one of the latest-flowering plants in the French calendar, blooming from September into November when few other flowers are available, making its nectar-rich blooms a crucial food source for pollinators such as hoverflies, bees, and late-flying butterflies. An ivy collection, in other words, functions as a late-season lifeline for exactly the community that surrounds you.
A region under pressure
The Nouvelle-Aquitaine Region committed itself in June 2017 to the implementation of a Regional Plan for Pollinators, and the five Regional Natural Parks of Nouvelle-Aquitaine — including the Parc Naturel Régional du Marais Poitevin — have developed an inter-park action plan to limit pollinator decline. The pressures of intensive agriculture, pesticide use, and hedgerow loss are real and well-documented across the region, making year-round - with year-round evergreen structure, late-flowering ivy, and open ground supporting ground-nesting bees — more ecologically significant than their size might suggest.
An Evergreen for All Seasons — and All Weathers
The most enduring quality of Hedera, in the end, is not any single characteristic but the remarkable breadth of its adaptability. It grows in deep shade and full sun. It tolerates acid soils and alkaline, clay and sand, coastal salt spray and urban pollution. It is evergreen, which in a garden context means it provides structure, colour, and wildlife value through every month of the year, including the grey depths of February when most of the garden has long retreated.
To watch 'Parsley Crested' with its sculptural, ruffled leaves intact after five days of forty-degree heat, or 'Tiger's Eye' holding its luminous variegation in conditions that might bleach a lesser plant, or the quietly dignified 'Erecta' standing unmoved like a small green sentinel — is a source of genuine amazement. And a reminder that the most underestimated plants in the garden are often those we think we know best.
Hedera rewards attention. It rewards observation. It rewards, as this week has demonstrated with some force, the gardener who trusts it with a proper planting in open ground and then - perhaps most importantly - has the patience to let it find its feet.
The author is the Cultivar Registrar for the Royal Horticultural Society and a specialist collector of the genus Hedera.
https://www.ishs.org/sci/icralist/11.htm