Green Services Direct

With our summers becoming hotter, find out how to make your garden more resilient to the scorching heat

Last summer was extremely hot and dry. Temperatures broke the 40C mark for the first time, leading the Met Office to issue its first-ever red warning for extreme heat.  It was the driest summer in the UK since 1995 and the sixth driest since records began.

The scorching weather and months of low rainfall dried up rivers, damaged crops and sparked wildfires, with an official drought declared in large parts of England. Our poor old gardens also suffered or at least the plants did that are suited to milder weather. Read our top tips to gardening in a changing climate.

Look to the Mediterranean

Gardens in the south/south-east of England will be most at risk of drought during hotter summers. The good news is “drier summers will provide genuine horticultural opportunities as well as constraints,” says a Royal Horticultural Society (RHS) ‘Gardening in a Changing Climate’ report.  Take inspiration from Mediterranean species that are well adapted to coping with hot, dry climates. Leaves can be an indication; if they’re hairy, waxy, spiky, scented, silver or needle-like, the plants are likely to thrive in hot sun. Think lavender, rosemary and evergreen fir trees.

Prolonged rainfall in winter should not prove a problem either as Mediterranean regions have significant levels of winter precipitation, but the soils themselves are often rocky and free draining. If your garden has a heavy clay soil, digging in some grit or sharp sand can help with winter drainage.  Sun-worshipping plants won’t thrive in wet, water-logged soil.

Choose heat-tolerant plants.

Choosing plants that can cope with hot dry summers will help future proof your garden. The furry silver leaves of Stachys byzantine (lamb’s ear) are a clue that this plant can cope well with heat and drought. Ornamental grasses thrive in hot weather and can add texture and movement to your garden. Examples include Cortaderia Richardii (Toe Toe) – a New Zealand pampas grass and stipa gigantea (golden oats).Shrubs likes jasmine, oleander, plumbago also do well in hotter climates as do some climbers, including passionflower, bougainvillea or solanum jasminoides. Drought-tolerant perennials include dahlias and geranium phoeum (dusky cranesbill).  Don’t forget to consider succulents like cacti which are well suited to hot and dry conditions and require little watering. Thick waxy leaves help reduce moisture loss.

Greater use of shade in garden design

Shade will become a more important element of garden design, predicts the RHS.  Awnings, pergolas and trellises can be used to create shaded areas for outdoor living and dining.  It’s not only plants that can start to wilt in the hot weather, but people too.

You might also want to consider using a shade cloth – a light, breathable fabric that can be draped over plants to block a certain amount of sun, anything from 20% to 95%. It is used mainly to protect tender nursery seedlings, heat-sensitive leafy greens like lettuce and other vegetables that may be stressed by intense sun.

Plant trees and shrubs

Trees and tall shrubs are natural shade providers. Green-fingered gardeners have often viewed shade as a problem as some flowering plants, such as roses, require full sun to thrive. Houses with north-facing gardens are less popular than sunnier, south-facing ones. But with climate change we’re likely to see hotter temperatures that make gardens uncomfortable and more plants suffer from heat scorch. Growing trees and tall shrubs to create shade will create cooler conditions and encourage us to spend more time outside.  The addition of shade loving plants along with plenty of well-rotted compost means you can still have plenty of colour in your garden.

Not all trees will do well in the heat. If you have space, consider planting an evergreen tree such as Mediterranean cypress that looks great all year with its needle-like fragrant leaves. Deciduous trees, such as hornbeam and silver birch, provide dappled shade in summer, while allowing sunlight through in winter. Other heat-tolerant trees include Ash, Acacia, cedar, Eucalyptus, juniper, oak, pine, poplar and silver Linden.

Mulching

Mulching is one of the most effective ways to protect the soil in a garden from becoming sun-baked. Use a mulch on flowerbeds and around shrubs and trees. Mulch can be made from a variety of materials, including pine bark, leaves, straw and grass clippings as well as inorganic materials like pebbles. Spreading a layer of mulch helps to keep the soil cool by reducing evaporation which means thirsty plants have more water. Additionally, mulch keeps the sun off the roots. It’s not so much a plant’s upper parts that are damaging by extreme heat as the roots. Mulch also helps to suppress weed growth which can compete with your plants for water and nutrients.

Improving the soil’s structure by adding organic matter, such as compost or manure, also helps to retain moisture.

Save rainwater

Last summer, many parts of England had a hose pipe ban. Using water butts to collect rainwater means you will use less mains water to keep your plants watered during the hot summer months. Connect a water butt to the down pipe from your house roof. Improve water capture by installing extra water butts or a larger than standard one to ensure a better water supply over the hot summer. Guttering can also be fixed to your shed and greenhouse to conserve water.

Water plants in the cool of the evening to reduce evaporation. Try to avoid watering plant leaves in direct sunlight as they can become scorched. When you water it’s important to ensure all layers of the soil in the root zone are wet. Regular light watering encourages shallow rooting of plants and makes them less drought resistant.

Plant in pots

Plants exposed to full sun are likely to have a tougher time in a heatwave. Here it can help to plant in pots. With a week of scorching hot weather ahead, even sun-loving plants may be happier relocated to the shady side of your home or in partial shade under trees. Again, mulch the compost or use moss on top to prevent evaporation and water in the evenings. Stand the pots in saucers so that water isn’t wasted as it runs through. Fill the post with fresh compost if it shrinks away from the side of the pot and leaves a gap,

Don’t mow the lawn in a heatwave

Lawns are fairly drought resistant. With no rainfall in a heatwave, lawns turn yellow brown and start to look parched. The grass will frazzle and feel crisp underfoot but don’t worry as the grass will quickly recover when the rain returns. One solution is to stop mowing during a heatwave as longer grass will help retain moisture and to avoid excessive walking on it – as that will result in bald patches. If you do want to water, use stored rainwater or grey water, such as washing up water, whenever possible, advises the RHS. New lawns, however, need watering regularly until well established if rain is in short supply.

Climate models predict that we’re in for more seriously roasting weather. But with a bit of thought our gardens can adapt to hotter temperatures and lower summer rainfall. Look at what is doing well and what isn’t in your garden and those of your neighbours. This is a strong clue to what is going to survive in future summer heatwaves.