Hailing from hot, arid climes, such as the Mediterranean and Australia, drought-tolerant plants can withstand prolonged periods of heat with no rain. The majority thrive in full sun, with their roots in well-drained soil or gravel beds that have been enriched with peat-free compost. As our climate changes, they ensure borders are a floriferous show of colour and scent all summer long, without the need to water.
Drought-tolerant flowers for colour
You can never have enough poppies, especially if you love bold colour, and they are extremely drought hardy. The majority love sun-baked, well-drained soil, with some capable of growing in shingle. Eschscholzia californica 'Orange King' blazes tangerine, while Papaver commutatum ‘Ladybird’ and Papaver rhoeas ‘Paradise' have sizzling-red blooms. Sow them direct in April.
Also fiercely red in summer are Linum grandiflorum 'Rubrum' (an easy annual flax that can be sown direct in April) and Potentilla 'Gibson's Scarlet’ (a fantastic perennial for the front of the border that can be planted in autumn or spring). For deeper red tones, plant pockets of the long-stemmed blood pink, Dianthus cruentus, at any time of year: in early summer, it sends up clusters of crimson flowers that hover above the grassy foliage and look marvellous growing through gravel.
Good colour foils for red include lime greens (such as the low-growing perennial Euphorbia myrsinites), blues (including the larkspur Delphinium grandiflorum 'Blue Butterfly’, which can be grown from seed in autumn or spring), and hot pinks (especially Lychnis coronaria, which is a fabulous short-lived perennial with downy silver foliage). Plant them all together for an explosion of colour in even the hottest, driest summers.
Drought gems for structure and impact
Drought-tolerant plants that have impressive size or shape can act as accents that bring a planting scheme together or simply add character and drama. Biennial mullein (Verbascum bombyciferum or V. olympicum) is one of the best, producing 1 to 2-metre candles of sulphur-yellow flowers from a rosette of furry grey leaves. 'Christo's Yellow Lightning', which the late gardener Christopher Lloyd named after an old (and rather slow) donkey called Lightning, is one of the best cultivars. Sow them now for flowers next year, after which they will self-sow.
Another excellent triffid for no-water borders or low-rainfall areas is the cardoon (Cynara cardunculus), which produces big thistle-like heads of purple flowers atop a 2 to 2.5-metre plume of silver leaves and can be planted in autumn or spring. The fennels have equal impact: with bronze forms (such as Foeniculum vulgare 'Smoky') offering lacy copper foliage and the giant fennel (Ferula communis) capable of producing a 3-metre tower of sunshine-yellow umbels.
For architectural spheres of flowers, globe thistles (including Echinops ritro, which can be planted in autumn or spring) send up a sea of electric-blue golfballs, and there is a wide range of alliums to choose from, including the 2-metre leggy 'Summer Drummer' and the football-sized Allium schubertii, which looks like an exploding firework at the front of the border; both can be planted in the autumn. Also weird and wonderful is Phlomoides tuberosa (syn. Phlomis tuberosa) 'Amazone', which has clumps of lilac-pink blooms dotted up 1.5-metre upright stems and can go in the ground in autumn or spring. Echinops, allium, and phlomis all mature into impressive seedheads, providing structure and interest through autumn.
Drought plants for scent
Many aromatic Mediterranean plants are highly tolerant of drought and high temperatures and fill the air with scent on warm days. Several – including lavender, rosemary, cistus, and curry plant (Helichrysum) – are evergreen shrubs that are best planted in early autumn or spring. Pinks (Dianthus), such as 'Devon Wizard', are ideal for the front of a gravel border and will release their incredible clove perfume in sheltered sun; they can be bought as summer bedding or planted as evergreen perennials in spring.
If you have space, the Australian mimosa (Acacia dealbata) is well worth growing as a large shrub or medium-sized tree. In late winter, it morphs into a wondrous cloud of deliciously scented yellow pom-pom flowers that perfume the air into spring. Although a weed in Provence, it is rather fussy here – requiring very well-drained neutral to acid soil in full sun and dislikes our colder regions – but in the right spot, it is a drought-tolerant joy.
Drought flowers for wildlife
Provide food for pollinators throughout heat waves by growing nectar powerhouses that thrive with minimal moisture. Butterflies flock to the honey-scented panicles of buddlejas (such as 'Royal Red') and the tall, airy flower clusters of purple top (Verbena bonariensis), which both bloom in late summer and early autumn and can be planted in spring or early summer.
Bees will fill the garden with contented humming if you grow lavender (especially forms of Lavandula x intermedia, such as 'Sussex') or nepeta (for instance, 'Six Hills Giant'); both form fragrant mounds of purple blue in summer and look great lining a path. Bees are also partial to salvias, including the papery pastel spires of clary (Salvia sclarea). All of these bee bounties can be planted at any time of year, although early autumn or spring is preferable. However, both sea hollies (Eryngium) and border stonecrops (Hylotelephium) can go in the ground now, in early summer: both are drought-proof and will provide pollinators with nectar in spring and early autumn, as well splendid seed-heads to adorn the garden through the cold months.
