As the UK experiences more frequent heatwaves, gardens are becoming increasingly stressed, with signs of trouble including yellow lawns, wilted plants, and drooping flowers. Garden experts advise against assuming that showering plants with water or cutting them back aggressively will help them recover, as this can sometimes do more harm than good.
According to Steve Edney, co-founder of The No Name Nursery in Sandwich, Kent, the best approach is to “hold your nerve” and avoid pruning shrubs until next spring, when new leaves have formed and it’s clear what has died and what hasn’t. Edney notes that some plants can enter a dormant state, appearing dead but still alive, and pruning them too soon can be costly.
Recovering from Heat Stress
For flowering perennials with stressed top growth, Edney recommends cutting them back to the ground, as this will encourage new basal growth development as the weather cools down. He also suggests observing which plants have done well during the dry period and considering adding more of those or similar plants to the garden.
Naomi Jones, a horticulturist at bulb supplier Farmer Gracy, notes that summer-flowering bulbs, such as dahlias, are suffering in the heat, with some customers reporting stunted or deformed plants. However, Jones reassures gardeners that dahlias are resilient and can recover if given proper care, including regular watering and protection from red spider mites.
Jones advises watering dahlias in the evening, rather than during the heat of the day, and avoiding over-watering, as this can do more harm than good. She also recommends using grey water, if possible, to conserve this precious resource.
When it comes to watering, gardeners should prioritize plants that are showing signs of stress, such as wilting or yellowing leaves. Water should be applied thoroughly and slowly, allowing it to reach deep into the roots, rather than simply running off the surface.
The best time to water is in the mornings, according to Monty Don’s heatwave advice. If you miss the morning slot, wait until early evening, which will prevent water from quickly evaporating. A good watering can, such as the Haws watering can, can be a valuable investment for gardeners, allowing for precise control over water application.
After the heatwave has ended, applying a generous layer of organic mulch, such as homemade garden compost or leaf mould, can help to combat dehydration and improve soil health. This should be applied around 6cm deep, keeping it slightly away from the base of plant stems to prevent waterlogging.
As plants begin to recover, gardeners should assess their repeat-flowering plants, such as roses, pelargoniums, and dahlias, and remove faded blooms to encourage further flowering. Regular deadheading can help to redirect energy towards producing new flowers, and can be done using sharp secateurs, such as Niwaki’s sentei secateurs.
Long-term Strategies
For lawns that have turned yellow and dormant during the drought, it’s essential to wait before mowing, raising the mower height slightly to allow the grass to restore itself and produce fresh green growth. Lightly scarifying and overseeding bare areas can also help to revive the lawn.
Gardeners can also take steps to adapt their planting choices to the increasingly frequent heatwaves, selecting drought-tolerant plants, such as fragrant lavender, hardy rosemary, and sedum, which require less moisture.