Plants for a hot summer
This bout of hot weather has served to remind gardeners of the precious value of water and the vulnerability of plants to the vagaries of the weather.
How can we create gardens that survive one of the wettest winters we’ve had in a long time, with two or three rounds of snow thrown in for good measure, followed by a drought and possible hosepipe ban.
First and foremost it’s about the soil. If we want a garden that can sustain drought tolerant plants then we need soil that (ironically perhaps) drains freely in order for these plants to survive enduring British winter rains, which many will not be used to in their native environment. Adding sharp sand to soil of course will improve drainage in heavy soils but the best solution is to incorporate organic matter such as compost or manure as this both holds onto water needed by plants whilst providing air pockets through which excess water can drain.
Then the second most important element is to reduce evaporation. Adding two inches of much, whether compost, straw, gravel or even bark chippings, not only reduces soil compaction caused by winter rain but also helps retain soil moisture and keep soil at a more constant temperature. The impact of a good mulch cannot be overstated and the difference in plant health between one border with mulch and another without is dramatic. Organic mulches such as compost, leaf mould or straw are absorbed into the soil in time further enhancing the soil’s structure.
Plants that are drought tolerant may seem to derive from warmer climes but they need not be delicate. After all it has been known to snow in Jerusalem. Some drought tolerant plants such as Lychnis coronaria, Valerian, Verbascum or Scabious are happiest on chalky soils; others such as Achillea, many irises, Salvia, lavender and Anthemis prefer a sandy soil. But add a reasonable amount of compost to either soil type and most of these plants are happy as long as the soil is free-draining. If you’re uncertain of specific plants to use then nature has some pointers for you. Silver leaves reflect heat better than green and are an adaptation to hot climates so plants such as lavender, olives and Artemesia can survive spells of dry weather. Narrow leaves are also an evolutionary device designed to reduce foliar water loss by minimising leaf surface area so plants such as lavender, rosemary, Grevillea and Pinus are all going to cope well with low water levels. Some favourite shrubs for dry weather would be Abelia, Olearia, Perovskia and of course our native mainstay Buxus (commen box).
Planting smaller specimens in spring will help ensure plants get used to their environment – newly planted larger specimens will be very thirsty until well established. When all else fails it is advisable to think ahead with an environmental hat on. So get those water butts connected to your downpipes, and when push comes to shove and a water pipe ban kicks in use bathwater.