Climate change plants: drier
Helen & James Basson MSGD recommend plants for dry conditions
Climate change will not occur overnight, but some areas of the UK are already becoming more suited to a Mediterranean planting style. We should celebrate the plants that would do well in these conditions, and perhaps in the future Britain will be producing olive oil instead of cider!
By adapting a planting palette with plants that can survive in these harsh conditions, we can create a stable ecology based on survival of the toughest. There are a series of structural landscapes that we find ourselves particularly drawn to, providing endless inspiration for creating gardens. In the steppe landscape, we have low-level plants in very shallow soil with high diversity. This can teach us about alternatives to our traditional British lawn – a serious consideration as hosepipe bans become more frequent and water increasingly precious.
Instead of the large open expanses of grass which are often the main component of a garden, it is perhaps time to rethink the balance, creating larger areas of vegetation that require little or no irrigation, with smaller zones nearer the main living areas watered more often (although still sparingly) to increase summer flowering. This can be punctuated with carpets of Zoysia tenuifolia or thyme that require much less irrigation than traditional lawns – something nurseryman Olivier Filippi advocates in his book The Dry Gardening Handbook: Plants and Practices for a Changing Climate.
Going for gold
Alternatively, we can really bite the bullet and embrace the varying tones of brown, silver and gold that summer dormancy naturally gives us in these dry environments, and not water at all. The prairie landscape demonstrates taller grasses as a dominant species, interspersed with self-seeding annuals and perennials. In the heat of summer, these grasses create a golden glow, adding architectural interest and movement in what can be an oppressive climate. Two of our favourites are Achnatherum calamagrostis (Stipa calamagrostis) for its grace, and the interesting, elegant Ampelodesmos mauritanica, which does well in the right location if the soil is well drained and poor. It can get heavy and pampaslike if the soil is too rich and wet, but it is particularly successful on rocky steep banks.
Sub-shrubs grow where the soil is slightly deeper, these are the plants that maintain the structure of the planting scheme through the hot summer months. A combination of natural domes such as Dorycnium hirsutum and Dorycnium pentaphyllum, contrasting with grasses and perennials like various Phlomis and Lomelosia cretica – stunning in flower, but equally beautiful when the dried seedheads remain. On the lower level are fillers such as Teucrium flavum and Teucrium x lucidrys to keep the ground covered and weeds at bay.
Another plant worth noting for its form is Euphorbia rigida, possessing a great leaf structure and self-seeding without being invasive. It reacts well to being pruned after flowering and holds its dynamic form better than the similar Euphorbia myrsinites. This idea of form is of utmost importance in a dry climate, making the difference between a garden and a landscape. In one of our recent conversations with Olivier Filippi, he discussed how form provides interest, rather than flowers and colour, in the heat of summer and early autumn.
By intelligent pruning post-flowering, we can emphasise the contrasting shapes in the garden, and the aromatics; lavender, rosemary, Cistus and Salvia thrive in poor soil and lend themselves to being lightly pruned. It is the deep-rooted taller shrubs that form the skeleton upon which the Mediterranean landscape hangs. Typically one or two species dominate – Pistacia lentiscus, Teucrium fruticans, Bupleurum fruticosum, Olea europaea or Phillyrea angustifolia are among the most common. They are low in density but still cover the ground successfully, thus decreasing weed competition. They need only an occasional prune to retain a loosely manicured quality.
Potentially taller than we would traditionally expect to plant, these species are the most efficient and cost-effective way to cover the surface area of the garden, with one plant per m2 in comparison with nine per m2 for prairie areas. By using these taller plants in greater volume and decreasing the lawn areas, we suddenly start changing the entire spatial feeling of a garden.
In all these ecologies, the key is diversity – the more diverse the planting palette, the more resistant it is to climate change. Deciduous oaks may start to decline in the UK as a result of warmer, drier temperatures, but evergreen oaks will take the stand and become more dominant. Diversity gives more interest in colour, texture and tone, but also increases the potential for natural selection as evolution occurs due to the ongoing changes.
No discussion on dry gardens would be complete without acknowledging the importance of the mineral elements. In the Mediterranean area, we are naturally drawn to open areas which we can easily access due to shallow soil and the presence of rock and scree. Replicating this in a garden creates a pause in an otherwise complex landscape, thus replacing the use of lawn aesthetically.
Could we see the Brits turning to pétanque rather than football and cricket in these times of changing climate as land use adapts? Both Filippi’s and Beth Chatto’s gardens embrace this. Chatto blends empty and fuller planted areas with one material – gravel. Filippi dug out paths and mounded the soil on either side to create channels for water to flow (when it does rain, it rains hard), leaving raised areas for planting, allowing roots to stay high and dry while adding visual interest. An interesting interpretation of the future of the art of landform – instead of sculptural grassed areas, why not mineral undulating landforms that dry climate plants can thrive in?