The leaves are blowing off the trees in the wind and rain this week, but gone are the days when trees would be bare by Bonfire Night. Climate change has postponed autumn and left October a largely mild month, with leaves turning colour much later than 50 years ago. But a milder climate may not be the only reason behind the delayed autumn leaf colours and fall. Last year, scientists at Southampton University found that rising levels of carbon dioxide also prolong the life of the leaves. Experiments with trees fed extra carbon dioxide revealed that they held on to their leaves for longer and remained greener. The carbon dioxide helped make carbon rich substances that extended the leaf life, an effect entirely independent of the temperature.
October is also a last chance to see some wildflowers before the frosts kill them. The large dandelion-like flower heads of corn sowthistle poke up amongst tall grasses, and pale blue flowers of forget-me-not woodland edges. The daisy-like flowers of the gallant soldier appear on waste land, its name came from a corruption of Galinsoga, a Spanish botanist who brought it to Kew Gardens from Peru.
The white, umbrella-shaped flower heads of yarrow are still standing in damp patches with their elegant feathery leaves. Another interesting flower head is wild angelica, with a striking array of white flowers, often tinged pink, which stick out on stalks like small pom-poms. It can be found along water edges or damp ditches and woods.
