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The best hardy plants that will survive in exposed garden plots

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy Stock Photo
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy Stock Photo

After I moved from the tropical climes of central London to a windy hilltop farm in West Yorkshire, it will come as no surprise to hear that my mind turned to hardy plants. And by hardy I mean able to withstand 4 inches of snow in late April, while simultaneously taking a battering from fierce winds. No more foliage begonias for me.

Hardy seems to be synonymous with boring, but it doesn’t have to be that way. I’ve visited many northerly gardens in exposed areas that are as beautiful as any of the Kent Edens. Mount Grace Priory in North Yorkshire and Cragside in Northumberland are both sited on hillsides and have colourful, delicate-looking, but tough gardens.

I spoke to hardy-plant expert Annie Ali, who now runs her own garden-design business specialising in planting design. She has worked on some impressive projects in North Yorkshire, such as Scampston Hall gardens, which includes a large area of prairie-style planting designed by Piet Oudolf. Prairie planting works really well in colder climates, Ali assures me: “Many varieties of plants used in prairie schemes are often mid- to late-summer varieties. Which means they are late to form mounds of foliage, after the worst of the weather has cleared.”

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Charlotte Graham
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Charlotte Graham

Ali always starts by selecting plants based on their hardiness. “The varieties we use are mostly hardy down to at least H5 (-15C to -10C), so the cold doesn’t affect what we grow.” Growing plants to match your local temperatures means you can ignore Jack Frost when he comes a-knocking. Exposed gardens have to contend with strong winds, too, and Ali explains that prairie planting is well adapted to this.

“They naturally grow in low-nutrient soil, so the plant roots go down very deep searching for water and nutrients, and this anchors the plant well into the ground, so wind rock is minimised.”

One couple who know a fair bit about gale-force winds are Michael and Allison Mitchell, who run the Chelsea award-winning Slack Top Alpine Nursery (slacktopnurseries.co.uk), located 1,000ft above sea level near Hebden Bridge, West Yorkshire.

“The main challenges are cold and wind,” they tell me, but add reassuringly, “alpines are a good choice for an exposed garden.” The Mitchells have used these diminutive plants that originate from mountainsides to amazing effect: “They’re adapted to surviving with a short growing season, cold temperatures, high winds and freezing conditions.” If your garden ticks these boxes, alpines are a good solution.

In recent years, I’ve been on a mission for low-maintenance, high impact window boxes, and while in London I turned to succulents. Speaking to the Mitchells, however, it strikes me that alpines are the obvious answer for creating a naturalistic perennial look on a smaller scale in pots or window boxes.

Allison offers one word of warning: “Heavy rainfall can be a problem, alpines don’t like wet feet all winter, however it is easily rectified by adding plenty of grit to the soil, and providing winter protection, if necessary, in the form of a cold-frame roof.”

Hardiness ratings explained

Plants are given a rating by the Royal Horticultural Society to indicate the lowest temperatures at which they can survive. For most of the UK, -15C is the lowest temperature we can expect, and any plant with an H5 to H7 rating is a toughie. In coastal or mild areas of the country such as London, this can stretch all the way up to H2 or even H3 in sheltered gardens. But the UK can usually count on some nights of zero temperatures outside.

  • H1a: 15C or higher

  • H1b: 10C to 15C

  • H1c: 5C to 10C

  • H2: 1C to 5C

  • H3: -5C to 1 C

  • H4: -10C to -5C

  • H5: -15C to -10C

  • H6: -20C to -15C

  • H7: -20C or lower

The best tough plants, according to Annie Ali

Flower power for sun

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy

Achillea (H7)
“Cultivated varieties of achillea, such as ‘Summerwine’ and ‘Walther Funcke’, can struggle,” says Ali. “But ‘Terracotta’ and ‘Inca Gold’ are much happier to withstand the cold and wet.”

Echinacea (H5)
There are so many to choose from and they can be reliable if the ground freezes. “‘White Swan’ looks great with golden grasses, ‘Hula Dancer’ has height and E. paradoxa gives a dash of yellow.”

Hylotelephium spectabile (H7)
Mound-forming sedums tolerate both winter cold and summer drought.

Grasses for texture

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Gap Photos / Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Gap Photos / Alamy

Festuca mairei (H7)
One of the best ornamental grasses for cold sites, this little-grown plant is native to the Atlas Mountains of Morocco. Forming a dense mound of evergreen foliage, it’s a great specimen plant.

Sesleria nitida (H4)
An early grass to flower in May, and it’s quite a low one, which is good as it blends well with spring bulbs.

Panicum virgatum ‘Squaw’ (H5)
Quite late in the season, but it has lovely airy flowers and good colour. A great grass en masse or mixed in among perennial flowers to create a soft feel.

Sturdy shrubs

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy

Pyracantha spp. (H6)
An evergreen, with spring flowers and autumn berries, pyracantha provides cover for insects and food for bees and birds. Flowers are pure white and berries range from red to orange and yellow.

Pinus mugo (H7)
One of the best compact conifers that stays compact, though eventually it will grow to 3ft-5ft over a decade or two. Excellent hardiness against winds and cold.

Rosa glauca (H7)
This is a deciduous species rose with red stems, greyish-purple leaves and pink flowers, followed by almost spherical red rosehips.

Jack Wallington’s favourite hardy plants to grow

Perennials for part-shade

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy

Astrantia major (H7)
‘Shaggy’, ‘Buckland’ and ‘Ruby Star’ are my favourites, but there are many other cultivars easily grown in the sun or part-shade. Deadhead for repeat flowering in summer.

Digitalis ferruginea ‘Gigantea’ (H6)
Spires of rusty-orange in summer, works well with grasses, as well as white, yellow and plum-purple flowers. Will gently self-seed. Our native foxglove, Digitalis purpurea, is also adapted to the coldest spots.

Persicaria amplexicaulis ‘White Eastfield’ (H7)
My favourite of the current white cultivars, its petals drop, unlike ‘Alba’, which turn brown on the plant. White glows in shadier spots, but shades of pink and red will be equally as tolerant.

Tough bulbs to plant in the garden

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy

Galanthus spp. (H5)
Snowdrops are as hardy as they come, bringing much-needed brightness to shadier spots at the end of winter.

Narcissus spp. (H6)
If you’re in a cold, exposed spot, you’ll welcome the bright yellows of daffodils as a sign spring is on the way. I prefer the white and pale primrose-yellow varieties.

Allium hollandicum (H6)
The onion family is cold-tolerant, although doesn’t like the winter wet as much as snowdrops and daffodils. Add a handful of grit on planting to help this, though I find the typical large globe cultivars all self-seed happily.

Recommendations from Slack Top Alpine Nursery

Spreading ground cover

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Getty Images / Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Getty Images / Alamy

Gypsophila repens ‘Rosea’ (H5)
A semi-evergreen creeping gypsophila, with pale-pink flowers all summer, which forms a spreading, weed-suppressing carpet. Plant at the front of borders or trailing over walls.

Erysimum kotschyanum (H4)
With dark evergreen leaves topped with bright yellow spring flowers, this small wallflower doesn’t look like its bigger relatives, but it’s a little toughie. Forms dense mounds and is slow to spread, so plant a number of them to suppress weeds.

Anthyllis vulneraria var. Coccinea (H6)
I can’t find its official hardiness rating, so this is a guess. This is an exotic-looking scrambler with orange-red flowers. Grow in dry soils.

Alpines for window boxes and raised beds

best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy
best hardy most tough plants shrubs uk 2021 to buy garden exposed grow cold weather survive winter - Alamy

Kabschia saxifrages (H4)
Cushion-forming plants that flower early in spring in a variety of colours, slowly increasing in size. Perfect for troughs, gravelly raised beds and between cracks in walls and paving.

Saxifraga x burnatii (H4)
Diminutive silver leaf rosettes that fire up 6in sprays of white flowers in summer.

Draba rigida var. imbricata (H4)
Its tight little mounds of leaves are resistant to all weathers, and yellow flowers appear in spring, smothering the plant.

Lewisia ‘Little Tutti Frutti’ (H4)
Small but show-stopping flowers in vibrant orange, pink, peach and white. Flowers in early summer and sometimes again in late summer.

How to create shelter

In an exposed or cold location, there’s no escaping the fact that you’ll need to use a range of shelters to grow a wider variety of plants. They serve to protect from wind and rain, and in enclosed spaces can raise the air temperature to create a mini microclimate. Shelter can come in a number of guises:

  • Perimeter hedging: on exposed sites, hedging acts like a sieve to slow down the wind, and is essential if you want to plant perennials to transform bare hillsides into sanctuaries. Evergreens such as yew are useful, but as most perennials grow in spring and summer, deciduous hedges are as effective.

  • Polytunnel or greenhouse: both serve the same purpose, in allowing you to significantly extend the growing season, especially with heating. Under cover, you can grow seedlings earlier in spring; tomatoes, aubergines and chillies later in summer; and hardy salads through winter. Needless to say, in an exposed position they need to be very well secured.

  • Cold frames: these mini greenhouses are useful for housing hardy seedlings and cuttings over winter, and for starting seedlings in spring.

  • Horticultural fleece: use fleece pegged or weighted gently over plants growing in soil to shield them from frost and wind. Fleece also warms the ground and air beneath them by a degree or two. In spring, the extra warmth can bring growing conditions forward by as much as a month.

This article has been updated for December 2021.