Hydrangeas are at their most stunning in summer, but July heat can cause serious damage if gardeners fail to mulch. According to experts at Gardening Know How, failing to mulch these flowers during hot weather is a big mistake that can lead to leaf curling, browning, and reduced blooming next year.
Why Hydrangeas Suffer in July Heat
July is usually one of the driest months across the UK, and hydrangeas can suffer even with frequent watering due to their shallow roots, which cannot retain much moisture. Transpiration, the process through which plants lose water via their leaves, can happen swiftly in hot conditions, putting immense pressure on hydrangeas. If leaves are curling, browning, or looking crispy, it's an unmistakable indication that heat damage has taken hold and the plant requires immediate care.
Hydrangeas subjected to extended heat stress will produce fewer flowers next year, and old wood varieties are likely to fail to bloom at all, as their buds will have sustained too much heat damage to survive. Should the overheated soil damage the roots, the plant will struggle increasingly to take up water, which can prove fatal for hydrangeas left untreated or those still establishing themselves.
The Mulching Solution
Experts at Gardening Know How explained: "Bare, dark soil around your hydrangeas acts like a heat sink. The soil absorbs a lot of the heat from the sun, cooking delicate roots underground and causing moisture to evaporate quickly. Hydrangeas tend to suffer from this heat and dryness in the summer, so take action to minimise the impact."
The best thing you can do is mulch generously around each shrub. Two to three inches of mulch does several things to support healthy plants: it regulates the soil temperature, keeps it cooler, holds moisture, and suppresses weeds. All essential for growing those stunning, billowy hydrangea blooms.
How to Mulch Properly
Mulching is a simple gardening method that involves covering the soil surrounding a plant with organic material, helping to protect it during the most extreme weather conditions. Throughout the summer months, wood chips or straw make the most appropriate mulch for hydrangeas, as they retain considerable amounts of moisture and keep the plant roots hydrated even during July's hottest spells. Adding mulch can also insulate the soil and protect the roots against sudden temperature changes, lowering the chances of hydrangeas experiencing heat stress.
Organic mulches can be easily found at garden centres and shops like B&M and Home Bargains. Simply heap the mulch around the base of each hydrangea, but leave a few inches around the stems clear to reduce the risk of rot and pests. That said, it's crucial to continue watering hydrangeas deeply once or twice weekly, as inconsistent moisture is one of the biggest and most damaging problems hydrangeas encounter in summer heat, according to experts.
