Climate change: Plants for dry gardens

Osborne House Gardens is a real source of inspiration for dry garden planting. Head gardener Deb Goodenough says: 'Gardeners from the mainland should come and see what we are growing, we've had the Mediterranean influence and weather for 150 years.'

Debs has lived on the Isle of Wight for 20 years, and she is convinced that the climate has become warmer. 'It's been a lot milder over the past five years, and the rainfall is more sporadic,' she says.

Palms and cordylines grace the terraces

In practice, this has meant more work keeping the grounds maintained to the standard expected. 'Our mowing contracts used to be issued for nine months of the year, but that's now 12 months, with the grass needing cutting even at Christmas,' Deb adds.

The walled garden is a particularly sheltered site, ideal for more tender plants, such as Erythrina crista-galli, native to South America. 'We planted it in 2000 and weren't expecting so much vigour – the huge red flowers will peak in August,' says Deb, whose husband Simon is head gardener at Ventnor. 'Nearby loquats have made big evergreen specimens in just five years. The ones at Ventnor have produced fruit.'

A more typical microclimate is on the terrace facing out to sea, where agaves in raised ornamental urns have been left out unprotected over winter. They sustained some winter damage due to cold and wet spells, but 10 years ago they would not have even considered leaving them unprotected. Cordylines and Chusan palms have also been left unprotected over winter. 'The Chusans were planted 10 years ago in a perfect spot with a bit of shade and some protection by the house,' explains Deb.

More evidence of milder weather can be seen in the narrow beds by the house. 'The zantedeschia were planted out in summer and were still standing tall over Christmas,' says Deb. 'I had to cut them down so they didn't swamp the emerging daffodils - normally the winter weather would have cut them down. We need to intervene a lot more these days.'

'A myrtle was given to Queen Victoria by Prince Albert's mother and a sprig was sent down to Osborne House to be rooted,' says Deb. 'Since then, it has been in royal wedding bouquets to symbolise the bride's innocence.'

Prince Albert had travelled in Italy before he met Queen Victoria, and he incorporated the Italian style and Mediterranean plants in the gardens at Osborne House. Back then, people copied the Royals, which accounts for so many evergreen oaks on the island. Debs explains: 'They're not native, but are a fantastic evergreen with a Mediterranean feel and they can be rejuvenated by pruning.'

The specimen cedars are a feature of grounds; the oldest was planted in 1718 and the rest by Prince Albert. He planted many trees – a stand of pines, evergreen oaks and arbutus in dry, gravelly ground survives well. Magnificent specimens of Magnolia grandiflora were planted 150 years ago against wall shrubs.

The Victorian heather bowl in front of the house planted with Erica arborea (Mediterannean tree heather) will grow to 3m (10ft). 'Soil here gets baked dry, but this heather will survive,' says Deb. 'It makes a good cut flower and will stay in the vase for around three weeks.' More of this heather thrives on a hot, dry bank with no irrigation. A honey scent was detected even in March.

Another similar-scented plant for dry spots is honey spurge (Euphorbia mellifera) – almost an evergreen shrub, its young growth is a feature and the flowers emit a heavenly aroma in June.

Bay laurel – Mixed hedging was a feature of the garden in Victoria and Albert's time and still is today. Traditional plants for a hedge were holly and cherry laurel, but for dry climates Deb recommends bay laurel. 'It copes well with being clipped and with the dry, and it will rejuvenate if cut back hard,' she says.

Fuchsias – These are planted along with camellias and zandeschias under the shade of trees. 'They do well and are so underrated,' says Debs. 'How many shrubs flower in August and copes with dryness and shade? I've got 20 hardy types.'

Osmanthus – Debs uses this as a shrub and a hedging plant. 'It copes with pruning and dry soil. It looks like holly, but it flowers just before Christmas whereas holly flowers from April to May.'

Ventnor Botanic Garden

Rock-based naturalistic planting at Ventnor

In 1970, Ventnor Botanic Garden was known as the Steephill Pleasure Gardens. The great plantsman and nurseryman the late Sir Harold Hillier recognised the potential of the site, nestling in the 'Undercliff' protected from north and east winds, and selected plants suitable for the shallow alkaline soils and salt-laden winds. After 10 years of mild winters, tender plants flourished, but the hard winter of 1986-87 and storms of 1987 took their toll.

Simon Goodenough became curator in 1986, and replanting took place in 1989-90, so most of what visitors see today are new plantings. 'It's been during the past decade I've really noticed the changes due to a warmer climate,' he says.

From lawns to rocks

'Around 17 years ago we had a lawn that went brown and horrible,' Simon recalls. 'There was lots of rock underneath, so in summer anything lush went to hell. Four years ago, we took up the rocks, put them on the surface and planted a naturalistic landscape instead.'

Annual seed is scattered and allowed to self-sow, and staff weed out what they don't want. As Simon has only five staff to maintain 22 acres, he's always on the look-out for low-maintenance approaches. 'There's very little soil, so trees tend to dry out and fall over, except Corsican pines and evergreen oaks.'

Plants that now thrive with the warmer weather

Clianthus punicens survives the winter

One strange-looking specimen turned out to be an ancient purple beech tree that is now on its last legs. Plants that used to struggle and are now thriving include Cistus from Crete, and Echium from the Canary Islands. Echiums grow on the bank while Geranium maderense self seeds everywhere. 'When I first came to the island, these would struggle to survive the winter, now they self seed year after year,' says Simon.

The cliff face is dotted with self-sowing succulents and Helichrysum petiolare. Mediterranean green wall lizards introduced by the Victorians are now doing well, as are European tree frogs. 'Our main limiting factor is the winter wet, so anything in the rainshadow side of the Andes should do well,' explains Simon.

The garden relies on voluntary contributions and Simon's thriftiness is evident throughout the garden. The wooden terraces holding a collection of cacti, agaves, housesplants and aloes were made from plywood sheets that a timber yard was about to throw out.

Plants from South Africa and Australia

The terraces of South African plants are carpets of green studded with flowers even in March. 'Two years ago, the bulk of the plants such as the large pelargoniums and yellow daisies of Europs overwintered outside,' says Simon. 'An aloe with orange flowers and a bird of paradise flower spike is not the usual March scene'.

The Australian garden is a more recent addition. Installed 18 months ago, the plants have settled in well, despite temperatures in the mid-40ºCs being recorded on the sunny bank in 2006.

Banksia, Bottlebrush (Callistemon), Grevillia and Mimosa are flourishing as evergreen shrubs in dry, sunny positions. Simon is experimenting with shrubby eucalyptus, putting them in as seedlings on rocky banks and letting their roots seek out moisture. As native British trees come under threat, could this fast-growing evergreen be a replacement?

Look further

*For travel to and from the Isle of Wight visit Wightlink Ferries

For more on climate change visit:
* Climate change solutions
* Protection against climate change
* Tomorrow's climate, today's challenge