My garden scorches and floods every year: here’s what I’ve learnt about planting for extreme weather

When Wendy and Christopher Bundy moved 100 yards down the road to their current home, they were well aware that the two-acre garden was prone to flooding. It is situated on the River Derwent’s floodplain in Elvington, North Yorkshire, and every year most of the garden lies under up to one metre of overflow from the river. The house is safe because it is built on the top of a gentle slope down into the garden, says Wendy, 78, who is now a widow. Moving away to a flood-free garden was never an option though: “I wanted to stay in Elvington because it’s a lovely village and I have lots of friends here, and I wanted a garden because I’ve always been a gardener,” she says.

The couple moved here in 2006 to downsize after their three children left home. Although the house is smaller than their previous home, the garden is half an acre bigger, and floods more extensively. The floods usually occur in January for several weeks. However, the river overflowed much earlier than usual last autumn due to the heavy rainfall, and the flooding has lasted for much longer than usual due to the continuing bad weather this spring, says Wendy.

“This last winter and spring has been a disaster because it flooded from October until March. The trees were still in leaf so I ended up with 5cm of silt from the river, with leaves in it. It didn’t do the lawn much good,” says Wendy, who manages the garden herself apart from outside help one half-day a week.

However, once the flood recedes, the garden springs back into life. By the summer it is once again its vibrant, burgeoning self, with the shrubs, trees, perennials, lawn and vegetable garden all flourishing. The trick, she says, is simply to grow the right plants. Luckily, the floods occur in the winter months, when plantings are dormant. Summer flooding is far more destructive for trees because they are in full growth so they are at risk of drowning, says Wendy. When a summer flood hit for 10 days in June 2007, she lost a lot of trees, mostly conifers; but because the soaking was relatively short-lived, the perennials survived.

Be clever with design and materials

When the Bundys moved in, the garden had “nasty” white brick walls round the perimeter that failed to keep the garden dry.

“It’s not dramatic, flash flooding, it’s very slow and insidious and comes up very gently,’ says Wendy, “but it’s much greater than you could possibly keep back with little walls everywhere.”

Wendy removed the walls and, rather than use hard landscaping to ward the river off, she concentrated on selecting plantings that can cope with flooding. “I’ve gradually learnt what will survive. You’ve got to experiment and learn from experience.”

The exception is in the vegetable garden, where she has built another tier to the raised beds to keep the plants above water level.

Design-wise, the garden has a formal layout, with trees, shrubberies, mixed borders of herbaceous perennials and shrubs, and a rose garden. It also has a vegetable garden, an orchard and a large pond. The paths are gravel or paved.

“I don’t use bark as a covering because when it floods it floats and ends up on the lawn,” says Wendy. “Gravel doesn’t move because it’s not flash flooding.”

Plant appropriate trees, shrubs and perennials

The crucial thing to remember, says Wendy, is that flooding is not the same as having a swampy or damp garden. Therefore, you cannot just select moisture-loving plants.

“It’s not a wet garden. Yes, it’s wet when it’s flooded but when the river goes down it’s a normal garden again. In the summer I have to water it. We’ve never had a hosepipe ban though, it would be ironic if we had.”

She has used trial and error to find what will survive: “I just fix things in and hope for the best.”

It tends to be common shrubs and perennials that can cope. “They’re called common because they’re in everyone’s gardens and they’re there because they’re toughies and that’s why they survive,” says Wendy. More specialist cultivars tend to die: “I’ve got a friend who runs a nursery locally and she has all sorts of posh things, but I can’t buy any because they’re too delicate.”

Trees

Wendy replaced the dead conifers with weeping willows. Other trees that survive the floods include oak (Quercus); Amelanchier canadensis; swamp cypress (Taxodium distichum); Acer platanoides; Acer palmatum; Prunus cerasifera ‘Pissardii’ (cherry plum); Pyrus salicifolia (pear); Corylus maxima ‘Purpurea’ (hazelnut), and hornbeam (Carpinus betulus).

“Trees take huge amounts of water out of the soil,” says Wendy. However, she cautions against planting too many trees because they would make the soil too dry for the rest of the year.

Shrubs

Wendy has created shrubberies and mixed borders, with sea buckthorn (Hippophae); Viburnum lantana and V. opulus (guelder rose); Mahonia; Picea glauca; Deutzia;  Physocarpus opulifolius ‘Diabolo’ and P. opulifolius ‘Dart’s gold’; Euonymus; Berberis; Hypericum × hidcoteense ‘Hidcote’; Symphoricarpos; Spirea; bamboo, and Escallonia. 

David Austin repeat shrub roses also do well. “They can look a little battered and take a long time to come back but they all survive.”

This success is contrary to expectations after a David Austin spokesman once assured Wendy that no rose can cope with flooding. “I thought ‘hmm, perhaps you should come and look at mine’. I grow a lot of roses here, they love the deep, rich soil.”

Perennials

As with roses, perennials can surprise you with their unexpected resilience, says Wendy. She is delighted that her lupins and Tradescantia survive the flooding.“The daffs always come up and flower, sitting in water up to their knees, and the camassias too. Not tulips though.”

Other toughies include Ophiopogon planiscapus (black grass); Geranium; Bistorta; Filipendula ulmaria (Meadowsweet); Lupinus (lupin); Geum; Iris sanguinea; Primula bulleyana; Carex pendula; Lysimachia; Humulus Lupulus ‘Aureus’ (Goldenhop); Eupatorium. Round the pond sit Iris pseudacorus; Hosta; and ferns Matteuccia struthiopteris and Osmunda regalis.

Plant fruit and veg in raised beds

“The vegetable garden was built with the flooding in mind so it’s on raised beds the size of an allotment,” says Wendy.

Because most vegetables are annuals, the water has usually subsided enough not to affect sowing. “I don’t overwinter root crops such as parsnips though because the floods drive mice onto the higher land [from the river] and they eat them,” she adds. “I love my asparagus, which is a perennial, so I’ve built a raised bed on top of a raised bed and my asparagus is very successful.”

She also built a higher bed for her raspberries, which will rot if left in wet soil. Other fruit, such as blackcurrants and strawberries, survive annual soakings, although if they are left for a month or more under water they may not fruit until the following year. Wendy has an orchard of apple, pear and plum trees which all survive the water, even two-year-old saplings.

Make the most of the soil

Water abstracted from the Derwent supplies towns and cities including York, so it is of generally good quality. The regular flooding has created a fertile, deep alluvial clay. “I don’t have a single stone in the garden because it’s layers and layers of silt and alluvial clay. It’s a very good soil, the flooding improves it enormously,” says Wendy.

Choose pondlife carefully

‘I used to put a few goldfish in my pond every year because they helped with the mosquitoes, but then one year you’re cutting the hedge and there’s a skeleton of a [stranded] goldfish halfway up and you think ‘No, I won’t bother any more’,” says Wendy.

Frogs survive because they hibernate at the bottom of the pond.

Wendy does, however, have a problem with duckweed growing on the pond surface: “The flood and the wind come and my fence down the bottom of the garden gets decorated with it.”

Be prepared to work on the lawn

Each year, Wendy has to scrape off and hose down a 5cm layer of silt from the lawn when the floods recede. The grass recovers, drying out in the warmer weather and helped by a dose of fertiliser. The not-so-good news is that worms drown in the floods. Those that manage to escape to a small patch of drier grass higher up the garden are pursued by moles also fleeing the water. They leave the lawn looking “like the measles”, she says. This year’s clean-up was particularly hard work because there were autumn leaves mixed in with the silt: “It’s a lot of grass to rake off.”

The other issue is that weeds such as buttercups thrive in the water: “So whether you could call it a totally grass lawn is another question. Luckily, I’m not that fussy about my lawn.”

Final word

“Be tolerant,” says Wendy. “And buy a good pair of wellies.”

Bridge House garden in Elvington, York, is open by arrangement until August 31 under the National Garden Scheme: ngs.org.uk