Gill Farrer–Halls ‘Gardening for our Changing Climate’ is packed with information to help us cope with less rain and more sun – it’s a book for the public but the following edited extract contains some useful tips.
For a drought resistant garden, you¹ll want to incorporate some kind of windbreak, dividing the garden into separate areas to slow the wind¹s path and ameliorate its drying effect. If the garden is small, then panels of trellis with lots of climbing plants is effective. This design also allows wind to gust through the gaps, so even a strong wind is unlikely to blow the trellis over. Hedges are a good alternative for a larger garden and encourage wildlife. Many hedging plants are both attractive and drought resistant.
For the large drought resistant garden project we considered and reviewed a real life project planned, designed and planted by Sara Jane Rothwell of Glorious Gardens. The original garden was a pretty basic affair as you can see from the before photo below. It consisted mainly of a large lawn with a group of mature beech trees at the end away from the house, with bushes and shrubs to one side and untended bare soil, ivy and a few straggly self seeded young trees to the other side. Developing this simple, unstructured space into a well designed, low maintenance, environmentally friendly and drought tolerant garden posed an exciting challenge.
To begin with, some basic construction and erection of new boundary fences was required to better define the garden space. The decision was made to opt for one-meter high oak posts, spaced out at 2.5m gaps, with three rows of tensioned galvanized wire strung between the posts. This provides a long lasting and durable fence. Because of the large size and woodland nature of the garden already providing natural screening, privacy was not considered a major issue, so the open style of the fencing was not a problem. In addition, new green oak was purchased from a local supplier for the construction of the terraced retaining walls and the arbour.
Obviously the beautiful mature beech trees would remain as a central feature, but careful consideration was needed to decide how to work round them. Firstly, as mature trees they were tall and caused a great deal of shade, which affects and limits what can be planted nearby. Secondly, it is very difficult to grow most plants under beech trees, so this affected how the immediate surrounding areas were planned and designed. However, as can be seen from the before photo on the right, the more formally designed and planted areas continues naturally and harmoniously into the less developed woodland area around and under the beech trees.
The finished garden as shown in the after photo above has a contemporary feel, with a clever mix of formal plantings integrated with natural woodland areas.
A large garden such as this must rely to some extent on physically powerful structural design and architectural plants, and here the beech trees give a strong focal point. Combined with interesting surfaces such as the bark mulch, a wide variety of different plants, and features such as the terraced beds and arbour the overall impression of the garden is one of Nature in harmony with human design.
The garden was designed to be environmentally friendly, drought tolerant and low maintenance. The photo below ( – ) shows two key green features. Firstly you can see the fenced area providing space for two compost bins – this is the best way to compost with one bin undergoing the composting process with the bottom layer just about ready for use while the other bin is built up with fresh vegetable peelings, grass clippings and so forth. The bins finally were installed once the planting and all the other gardening work was completed.
Secondly, you can see the thick bark mulch covering all of the surface area of the beds around the plants. Not only does this minimise moisture loss and make the best use of rainfall, but the mulch has been also applied quite thickly to discourage any but the most persistent weeds. With very few weeds having a chance to grow through, the amount of time spent weeding is much reduced. In this way, the natural state of the garden is undisturbed much of the time – encouraging wildlife to visit – and the soil structure is not broken down by repeatedly walking over it.
Choice of Plants
Plants were chosen for their suitability for the soil type and other of the garden¹s conditions such as sunlight, shade and exposure. Plants were also selected for their individual aesthetic qualities and for their ability to combine harmoniously into the garden as a whole. The natural, woodland style of the garden has been enhanced by a choice of plants that blend well together. Whilst some more formal, highly stylised or cottage gardens can take lots of different colours and flowers, the more natural feel of this garden is highlighted by keeping to mainly different shades of green with some white flowers and grasses.
One of the few exceptions is the pretty and dramatic red flowers that you can see have been carefully and generously interspersed amongst the other plants. This plant is the lovely penstemon garnet, or Penstemon Andenken an Friedrich Hahn. Penstemon garnet is a bushy semi-evergreen perennial that can grow up to 90cm in height, so the bright flowers are easily visible both above and through the other plants. Its narrow, dark green leaves help show off the bell-shaped, deep wine-red flowers, accented with white on the throat of the petals. Generally disease free, penstemon garnet tolerates almost all soil types and aspects so it fits in well to the garden¹s natural, low maintenance, drought tolerant remit.
The penstemons are particularly complemented by the Mexican feather grass, or Texas needle grass (stipa tenuissima). This deciduous grass has narrow, arching, feathery flowers of pale brown and pale green in summer. Ponytails is a hardy, easy to care for plant ideally suited to this garden.
Many drought-tolerant plants that are suitable for planting in Britain and other temperate regions come from the Mediterranean countries. The normal climactic conditions in the Mediterranean are hot, dry summers and cool winters with little, or even no, frost; conditions in which many drought tolerant plants thrive. For plants from these regions to survive winter successfully in Britain, you must select carefully only those varieties that are fully winter hardy, or be prepared to protect more vulnerable plants from frost.
There are a surprisingly wide variety of drought tolerant plants. These range from those capable of dealing with very arid, desert like conditions to those more suited to the less challenging conditions of semi-desert, and include some plants native to Europe. Many of these plants have flourished in the long, hot, dry summers of late, and – because desert climates often have very cold spells as well as hot – they need little or no frost protection.
Obviously the main feature of drought tolerant plants is their ability to survive with little and infrequent input of water, but what are the other characteristics of drought tolerant plants’
How Plants Manage Drought
Since the beginning of vegetation on this planet millions of years ago, plants have been evolving to cope with the different, sometimes hostile conditions they encounter. Perhaps most notable are plants that come in the category of Œsilvers and greys¹, such as mugwort, sagebrush, cotton lavender, artemisia, cinerarias and wormwood. These have fine hairs all over their leaves, which act as a defence against the drying effects of wind and sun.
Other plants protect themselves with leaves that have a waxy outer coating, whilst succulents such as agaves have rigid fleshy leaves and toothed edges, often tipped with sharp spines. A few plants have evolved in such a way as to have minimized or dispensed with leaves altogether to reduce moisture loss.
It is interesting to look at the traditional British and European garden plants that flourish in drought conditions.
For instance, plants as diverse as the periwinkle that creeps along the flower bed with its trailing leaves and bright blue flowers, and the stately bush ceanothus that bursts into masses of blue flowers in spring are both drought resistant, familiar favourites in the temperate garden. Also several varieties of the beautiful and hardy aquilegia, such as Dragonfly, the ubiquitous potentillas that produce their yellow or orange flowers in summer and the stately bay tree are equally familiar and drought tolerant.
Readers can buy this book directly from the publishers website www.angelapatchellbooks.com