Warm welcome from plants that love a place in the sun
Every summer sees one or other group of plants suffer to a greater or lesser degree in Irish gardens. The climate is about midway suitable for the plants that like a cool damp summer and those that like sunshine and heat. Usually, an average summer brings enough moisture and enough sunshine to satisfy both groups of plants. But sometimes the summer weather lurches dramatically to damp, cool, interminable cloudy weeks or, more rarely, to a long hot, sunny, dry spell as this year.
The best indicator plant is the rose. Most of the roses grown here were derived as hybrids from species native to France, Persia and China, all countries of continental climate where the rose parent species would get a cold winter and a reliably hot sunny summer. In an average year here, roses do pretty well and flower nicely.
But in a wet, cool and dull summer, roses often fail to open flowers, which rot on the stems, and the plants are afflicted by the wet-summer fungal disease black spot of roses, which can cause all leaves to be shed and flowering to be much reduced.
In a hot summer with plenty of sunny days, roses luxuriate, flowering profusely and free of the damaging black spot.
Roses root deeply and generally do not need watering - they are warm-country plants, thriving in great shows in the south of France and Italy, for example, every summer and this year here too. If anything, give them a mulch of garden compost to keep them going.
But there are lots of plants revelling in this weather. It is easy to tell which plants thrive naturally in dry soil and heat. They wear this information on their leaves and stems. Any plant with grey or silvery leaves, or small leaves, or leaves rolled back tightly at the edges, or with leathery leaves is naturally resistant to drought because of these tell-tale adaptations.
Another good indicator of drought resistance is a coating of blue green wax and fleshy leaves and stems that hold moisture in reserve, such as yucca and pelargoniums.
Mostly, these well-adapted plants originated in areas of Mediterranean-type climate: the region of the Mediterranean, California, South Africa, middle areas of Chile and Argentina, the North Island of New Zealand, and parts of south Australia and Tasmania. Most of the premier wine-growing areas of the world. For this summer, the Mediterranean climate has moved 1,000 or more kilometres north and has stayed put.
Examples of sun-lovers include lavender, cistus, rosemary, evergreen oak, Russian sage, phlomis, brachyglottis, hebe and callistemon which are luxuriant. All shrubs from the Mediterranean, except the last three respectively from New Zealand and Australia.
Flowers that are loving the sunshine are: African lily, Cape daisy, Paris marguerite, originally from the Canary Isles; and echium too, Argentinian verbena, Chilean fuchsia, Mexican cosmos, California poppies, nasturtium and morning glory from Brazil.
Trees that normally make do with the summer are delighting in the sunshine and heat, for instance, acacia, robinia, catalpa, koelreuteria, American redbud and paulownia.