Tony Hall, manager of the arboretum and gardens at the Royal Botanic Gardens, Kew says: "Many plants that withstand the heat are evergreen, so gardening with these plants means you can still have a colourful garden with foliage in shades from silver-greys thorough to glossy dark greens, all year round."
Hall's new book, Gardening With Drought-Friendly Plants, profiles more than 200 plant species and cultivars, and offers tips and advice on maintenance and pruning.
Here he suggests five drought-friendly plants that are happy to take the heat...
1. Rock rose (cistus)
"If I could only grow one group of Mediterranean plants, it would definitely be cistus, commonly known as rock roses. They are all evergreen, have a range of flower sizes and colours, are very attractive to wildlife, particularly bees, and most have aromatic foliage," he says. "My favourite is Cistus albidus, with crinkled, rose-pink petalled flowers, contrasting with soft, grey foliage - but there are many species and cultivars to choose from."
2. Scorpion vetch (Coronilla valentina)
"This bright and cheery plant has fragrant lemon-yellow flowers, which I love. It is evergreen and grows to around 1.5m tall, with its main flowering period being March to July, but it will often have a few flowers on it just about every month of the year," says Hall.
3. Lavender (Lavandula)
"Lavenders are aromatic dwarf shrubs and hardy just about everywhere. They all have scented flowers and foliage, and flower all summer.
"Commonly called French lavender, Lavandula stoechas is the showiest, with large flowerheads made up from many small individual flowers and topped with a tuft of purple bracts. Again, there are many varieties and colours available."
4. Dwarf fan palm (Chamaerops humilis)
"This palm will add a tropical feel in a garden and is very hardy. It will eventually grow a small trunk but is very slow growing."
"Euphorbias are a great group of plants. Most are evergreen, and some are herbaceous and die back in the winter, regrowing the following spring.
"E. myrsinites is low growing, with whorls of blue-green succulent-like foliage, topped with sulphur yellow flowers, in late spring. E. characias has tall stems, with the spectacular subsp. wulfenii, producing large heads of lime-green flowers."
Will they survive winter?
"All the plants I have mentioned will take some frost," Hall notes. "Many areas of the Mediterranean get regular winter frosts and plants have adapted to tolerate these conditions.
"What they will not tolerate is cold and wet or waterlogged soil. So they need good drainage. Apart from that, they will look after themselves once established."
What if you have heavy soil?
Improving soil drainage by adding shingle will help if you have heavy soil, Hall advises. As soon as new plants go in, they need a good watering. This applies to all plants, not just drought-tolerant, plants.
"Mulching with gravel importantly traps soil moisture in free-draining soil, reducing evaporation. It will also suppress weeds," he explains.
How should you treat new plants?
"These plants will probably need to be watered occasionally in their first season, but are then left to fend for themselves. Do not feed, as this will promote growth that isn't needed," he advises.
"Research your plants, checking mature sizes, so you get the right plant for the right place, and they will thrive with minimal maintenance. By choosing drought-tolerant species, you can create a waterwise garden with plenty of colour and interest."
Gardening With Drought-Friendly Plants by Tony Hall is published by Kew Publishing.