Plant diseases are at their lowest levels in the UK for years because of a cold, dry spring, meaning it could be a bumper year for apples, and popular blooms such as iris are likely to be spectacular.
The Royal Horticultural Society (RHS) said years like this may be few and far between in the future, as the climate becomes warmer and wetter, creating ideal conditions for pests. But this year, spring favourites such as quince and hawthorn are doing well, with gardener queries to the charity about plant diseases on their plots down 45% on last year.
Diseases including powdery mildew and fungal leaf spot have been kept at bay this year as there has not been the warm, wet or humid weather that encourages their spread. But that is the climate predicted for the UK in coming years.
The weather has been good news for Chelsea flower show, which takes place at the end of the month, as the unsightly fungal leaf spot is at its lowest levels in six years. It typically afflicts plants commonly seen at the horticulture show, including lupins and bearded iris.
Disease inquiries in general are at their lowest level for three years, when they were on the increase during humid springs. The RHS said that with showers predicted and the weather getting sunnier, there could be a surge in pests and diseases, and it has warned gardeners to keep an eye out for telltale signs of plant damage.
The charity advises mulching plants to help retain moisture levels and ensuring good air flow around plants such as roses, gooseberries and honeysuckle, which are vulnerable particularly if grown against walls or fences.
Dry spells are known to increase plant stress, which means they are more susceptible to diseases including honey fungus, the most prevalent plant disease in the UK.
Liz Beal, a plant pathologist at the RHS, said: “Reports of common garden diseases such as powdery mildew and fungal leaf spot are at low levels this year after a mild and dry start to the growing season. While this stands to benefit popular May blooms such as lupins, hawthorn and bearded iris, gardeners should consider the impact a change in the weather could have on their carefully cultivated plants. Prevention is always better than cure, so ensuring our gardens are healthy year-round is an important consideration for the UK’s 30 million gardeners.”
Experts at the charity expect this year to be somewhat of an aberration as a warming climate means plants are more likely to experience stress and become more vulnerable to disease. A changing climate could also make gardens attractive to new, imported problems.
The RHS has historically labelled some wildlife in gardens, including slugs and snails, as pests and advised gardeners on how to get rid of them. But now it is focusing on teaching wildlife-friendly horticulture and tackling more pressing matters including the rise of invasive species and plant disease due to global heating.
The charity recently said it recommended a more relaxed approach to slugs and snails, pointing out that although they eat plants they are important to garden ecosystems.