Buddleia – their flowering period may be a bit truncated but they seem happy to give it a go
Callistemon, bottle brush, a bit of a marmite shrub due to its spiky foliage, but definitely a heat lover.
Caryopteris – welcome pale blue flowers at the end of the summer
Cistus – should be able to cope unless planted in the last couple of years, when you may need to chuck a bucket of water at it every couple of weeks
Colutea – bladder senna. The commonest species is Colutea arborescens which grows into a small tree but I have the smaller Colutea persica var. buhsei which copes really well with a hot dry site. Lovely yellow/orange two tone pea-like flowers (scented and bumble bee friendly) followed by bladder fruits – pretty pinnate foliage – whats not to like?
Convolvulus cneorum – the hotter it gets the more this silver leaved convolvulus likes it!
Euphorbia – with their semi succulent stems most garden euphorbias seem to stand up well to heat and drought. The smaller, prostrate ones such as E.myrsinites seem to actually revel in it, with the taller characias types also coping well. An exception wood be E.dulcis which is a more fragile woodlander, whose stems need to be cut right down after a dry spell.
Genista and Cytisus brooms prefer the hotter spots in the garden
Grevillea – the cultivar ‘Canberra Gem’ seems particularly happy in my gravel garden this summer.
Hypericum – My ‘Rowallane’ bushes look as happy as they did at the start of June. Beware of H. calycinum, though, which can be very invasive.
Lagerstroemia indica crepe myrtle- this shrub/small tree actually needs a good whack of heat to produce its stunning clusters of late summer flowers – mine (I think it’s ‘Braise d’Ete’) also has amazing red autumn colour.
Lavender and rosemary – very drought resistant in the ground – less so in a pot.
Nandina domestica, heavenly bamboo – not a true bamboo but looks like one but much better behaved, this rugged little shrub seems to use water very efficiently, still produced creamy panicles of flowers in the hottest spells which lead onto clusters of red berries in autumn.
Phlomis – P. fruticosa with yellow hooded flowers or P. italica with pink flowers. Also the pale yellow russelliana
Potentilla – not one of my personal favourites but pretty drought tolerant
Tree poppy- Romneya coulterii – but the same warning about a suckering habit applies!
Roses – Being very deep rooted, most roses will survive a drought but the only ones in my garden that look supremely happy in a heatwave are the scotch briar roses Rosa spinosissima I have a double form, and Louise rates the creamy cultivar ‘Dunwich Rose’ – I bought Caroline and I one each named ‘Mary Queen of Scot’s’ in the sell off from the Binnys Plant stand at Chelsea this year, and it’s still looking remarkably chipper even though it’s still encased in its original small pot. They only flower once in early summer but have lovely ferny foliage and small dark hips. Beware though – if they’re happy they sucker like mad, so best grown in isolation
Shrubby salvias like Salvia x jamensis
Sambucus – All my ornamental elders such as ‘Black Lace’ are faring very well without water, and providing glossy and striking foliage among the perennials.
Santolina chaemaecyparissus – lavender cotton. a low evergreen shrub with silvery leaves (and a rather odd scent if you rub them!)
Sphaeralcea ‘Sour Up’, and ‘Childerley’ – these need a mild climate, but will flower for months in a hot, sunny summer.
Tamarix – often grown in hot windy seaside locations.
Teucrium chaemadrys – wall germander – low-growing late summer flowers looking like a glossy heather – seems impervious to heat or drought – very attractive to bees
Albizia julibrissin, the Persian silk tree, thank you to one of our followers who has put forward this little tree, that performs brilliantly in a heatwave
Catalpa – Indian bean tree. Can get big, but ours has lovely large leaves and gorgeous summer flowers, so if you do have the space, I can recommend it.
Eucalyptus – most have the ideal foliage for heat, and many have very attractive bark
Gleditzia triacanthos – the Honey Locust – we’ve never seen ours looking so happy!
The evergreen Magnolia grandiflora looks supremely happy in the heat, but it’s a whopping great thing – there is a dwarf version ‘Little Gem’ that would be more manageable in a smaller garden
Olive trees – these are becoming more of a common site planted in the ground in Southern England – they may lose their leaves in a late winter beast from the east, but seem to recover. Even in a pot they seem to exist happily on very little water
Armeria – thrift is okay in a hot spot
Bergenia – elephants ears also tolerate drought once they’re ‘dug in’
Epimedium for shady areas
Geranium macrrorhizum will provide good ground cover in semi-shaded places with scented foliage
Helianthemum – rock roses
Thyme and grounding hugging sedums for sunny areas
Clematis nepalensis – a rare clematis that actually loses all its leaves and goes dormant in the summer months (so avoids drought damage but does look alarming dead! ) but then springs to life in the autumn and flowers over the winter months
Ivies – their tough leathery leaves seem impervious to weather extremes and can also act as natural air conditioning if planted against a house wall.
Perennial sweet peas – Lathyrus species- seems very tolerant of heat and dryness, though they will go to seed quicker. This the very opposite of the annual species who loathe having dry feet!
Trachelospermum – evergreen either the white or there is a pretty creamy coloured one – very scented
Althaea cannabina – I can’t speak too highly of this wonderful hollyhock relative that shoots up in midsummer to present a diaphanous cloud of small pink flowers, dancing gaily no matter how hot it gets. Seeds itself around when happy.
Callirhoe involucrata – the purple poppy-mallow
Cardoon Cynara cardunculus
Diascia personata – recommended by one of our followers, apparently this has flowered non- stop throughout the heatwave
the perennial foxglove Digitalis ferruginea has been a lifesaver in my garden this summer, providing pretty bee-friendly vertical accents when others have faltered.
Echinacea – we’re getting reports from our followers that echinacea are coping well with the heat with Pallida, White Swan, Pink Parasol and Tomato Soup all getting the thumbs up
Echinops – globe thistles. They look right at home in the sun.
Echium – one of readers has reminded us that if your garden is mild enough to sustain them over winter several species of echium including the towering E. pininana will cope with heat and drought
Erodium – related to geraniums and pelargoniums these diminutive alpines form satisfying mounds of ferny foliage and flower all summer long on hot walls or crevices. There are lots of different species and cultivars, but beware, collecting them can be a bit addictive (but you’ll be in good company – my current favourite is the sulphur yellow Erodium chrysanthum)
Eryngium. With their deep tap root, referred to as ‘the old world’ species (E. plenum, alpinum, bourgatii, giganteum etc) they seem to thrive in drought, whereas the new world species (E. yuccifolium and pandanifolium) have shallower root systems that can struggle in prolonged drought, with the exception being the huge E. pandanifolium ‘Physic Purple’ which seems to need a long hot summer to prompt its massive flower spikes to make the effort
Hyelotelephium – Sedum – succulent stems and flowers protect them beautifully
Ipomopsis rubra – a flowering plant of the phlox family, also known as the standing cypress, or Texas plume
Kniphofia – red hot pokers, as their name suggests they like it hot!
Lychnis coronaria – rose campion, a short-lived perennial in either magenta, white, or pink-flushed. Seeds around when happy but never a problem
Nepeta – catmint. I cut mine back in the middle of this year’s very hot July, and it’s full of flowers (and hundreds of bees and butterflies) again now, without being given a drop of water.
Origanum – marjoram
Oenothera ( rests up during the day and comes to life at night)
Papaver rupifragum, the Spanish poppy – the name says it all, very happy in baking soil.
Perovskia – pruned hard in late spring to a woody framework, this will withstand really hot conditions with pale purple flowers for weeks in August and September
Verbena bonariensis – the plant that never falters!
Zauschneria – a species of willow herb from the dry slopes of California.
Annuals and biennials
Chicory, Cichorium intybus
Eschscholtzia – Californian poppies
Galactites tomentosa – the purple milk thistle. There is also a very refined white form
Verbascum – giant mulleins, producing a basal rosette in the first year and a huge flowering spike in the second summer. The cultivar ‘Arctic Summer’ comes highly recommended by one of our followers, and has apparently flowered magnificently in the heat wave
Briza maxima, quaking grass – can self-seed invasively but very happy (and pretty) in very poor soil
Dwarf Festuca glauca ‘Elijah Blue’ also good
Miscanthus nepalensis – a smallish slightly tender grass that produces gorgeous coppery golden tassels in a hot summer, common name the Himalayan fairy grass and also quite happy in a pot
Most grasses have evolved in hot, dry prairie situations so will cope with a British heatwave. The low-growing Stipa tenuissima is particularly joyful as is its taller cousin Stipa gigantea.
Bulbs, tubers etc.
Agapanthus – love the heat but will need a decent amount of water if grown in a pot
Crinum powellii – despite their large strappy leaves crinums are sun worshippers and will produce stunning white or pink scented lily-like flowers in early autumn if planted in the right place. They will however need a small mechanical digger to shift their enormous bulbs if ever you tire of them
Summer-dormant bulbs such as nerines and Amaryllis belladonna – soak up the heat and flower in the autumn
Pelargonium – obviously!
Sempervivum – house leeks
We’d love to hear about any other drought tolerant plants you could add to our list!