Sun and Heat in Gardening
The diversity of planting possibilities in full light is so vast that it would be impossible to do justice to the subject in this article. However, it would be useful to point out some of the hundreds of plants that tolerate extremes of heat and drought. The base of a sunny wall, a dry bank, and the “hot” side of a rock garden provide conditions which suit the kinds of plants that grow naturally in the maquis of the Mediterranean and the semi-desert-like conditions in Australia and North America. Such plants, with their toughened, often silvery foliage, easily cope with heat.
Many have beautiful and distinctive flowers, others have stately architectural shapes. The tall, creamy flower spikes of yuccas, for example, make superb living sculptures in a garden and are fully drought-tolerant. Most of the wormwoods (artemisias) have iiligree foliage in silvery tones, and gems like the delicate flowered Convolvulus cneorum are exquisite with their silver foliage and pinkish white blooms.
Many bulbs and corms thrive in hot, dry conditions too, from Mediterranean anemones and dwarf irises to various green, brown and purple fritillary species. Later in the season, the alliums relish heat, as do autumn-flowering amaryllis and crinum. The Mediterranean look Gardens with a reliably dry, bright, sloping area are ideal for a wide range of scented Mediterranean shrubs like lavender, myrtle, thyme and rosemary (both the upright forms and the trailing Rosmarinus officinalis ‘Prostratus’). Many cys-tus do equally well in such conditions (for example C. crispus, which has grey foliage, and C. albidus, with leaves verging on white).
Unless you can guarantee frost-free conditions over winter the tender, heat-loving plants will have to be put into containers and brought inside. This is certainly true of Nerium oleander, which is never going to be as big in temperate regions as one growing in the Mediterranean or California where it makes a massive flowering hedge; even so it is definitely worth its place on a hot patio.
Some plants, like the prolific, white-flowering Osteospermum ecklonis, can be risked outside over winter in most areas except for the very coldest, though it is still best to take cuttings in case the temperatures dip well below freezing and kill the parent plant.
Besides the ornamental plants, also consider fruit bushes like Citrus limon ‘Meyer’. Discovered in China at the turn of the century it gives good size fruit and is hardy enough to stand outside even in a disappointing summer. In contrast, the European olive tree can be surprisingly hardy, and ought to be grown more widely in unusually warm city centres like London.
