Freak weather leaves its mark as trees begin to show autumn colours
While the onset of autumn is controlled by temperature and day length, the unusually early colour being seen on trees such as maples, hazels, liquidambar and laburnum is a response to the dry soils left over from the spring, the RHS said.
The society has seen yellowing, and some red and brown tints, on leaves at its gardens at Wisley, Surrey. Fruits are also ripening several weeks early on apple and pear trees, while autumn raspberries and wild fruits such as hawthorn are ahead of schedule.
Guy Barter, chief horticultural adviser at the RHS, said: “We are certainly beginning to see plants beginning to show colour because of the unusual weather we have had.”
He said a reasonably wet winter was followed by an extremely dry spring, and despite rainfall since the spring, it had not been enough to counter extremely dry soils.
As a result, he said: “Trees and shrubs are under a lot of water stress. It’s not fatal because they are well adapted but it makes them get rid of their leaves.”
He said it was not a problem for the trees, which had a very good growing season because of the early warm weather and would be in good condition for next year.
However he said gardeners should give plants such as rhododendrons and camellia a “good soak”.
This season’s weather, with its midsummer rain, has also led to unseasonal blooms on winter flowering plants, including some hellebores, viburnum, mahonia and magnolias.