As the UK experiences its third heatwave of the year, with temperatures soaring to 36C in parts of Wales, horticulturist and broadcaster Peter Dowdall has issued advice on what not to do in your garden during extreme heat. Known as The Irish Gardener, Dowdall has 30 years of experience and warns that certain common gardening tasks can inadvertently harm plants.
Avoid Major Garden Jobs
According to Dowdall, a heatwave is not the time for substantial pruning, relocating plants, or dividing perennials. These tasks should be reserved for cooler conditions. He explains: 'Plants are already under pressure, so avoid unnecessary disturbance.' However, deadheading—removing spent flowers to encourage new blooms—is acceptable, especially in pots and bedding plants.
Do Not Feed Stressed Plants
Feeding a plant that is struggling in the heat can add more stress rather than solve the problem. Dowdall advises: 'Water first, allow the plant to recover, and only feed when it is actively growing again.' The priority should be water and improved growing conditions.
Do Not Panic About Lawns
Mature lawns often turn brown during hot, dry spells, but this does not mean they have died. In most cases, grass enters dormancy and will recover when rain returns. 'New lawns need more care, but established lawns are usually not the first thing to water,' Dowdall says. He also recommends raising the lawnmower height because cutting grass too tightly puts it under more stress.
Choose the Right Plants
Dowdall emphasises that heatwaves reveal where a garden is most vulnerable. If a plant requires constant intervention when temperatures rise, it may not be suitable for that location. Selecting appropriate plants is the most sustainable way to minimise watering. 'The right plant in the right place will always perform better,' he notes.
Practical Heatwave Advice
Dowdall's final recommendations include: prioritising new plantings and containers, watering in the morning or evening, mulching watered soil, protecting vulnerable plants, avoiding feeding stressed plants, and not panicking over established lawns. His advice aims to help gardeners care for their plants calmly and effectively during extreme heat.
