Everyone (especially in the UK!) appreciates a long hot summer, but the weather can make the Summer a struggle for plants…
This season’s berries are in abundance, but the strain of a long dry summer is showing on so many trees – Mountain Ash varieties and Crab Apple varieties in particular have had a hard job retaining all of their foliage. Birch have shed a quarter to half of their foliage. Shedding a quantity of their foliage helps the tree by reducing the amount of moisture it requires. This protects the secondary bud that can then re-leaf either when the rain comes again in warm weather or if the dry weather continues into late autumn – early winter. The bud will then leaf and grow the following spring. As the tree is stressed because of the dry weather and the leaves are dehydrated, this will allow fungal spores already attached to the underside of the foliage to attack the weakened leaves. Bacterial sprays are available to stop the fungus from spreading down the leaf vein into the secondary bud shoots. If the secondary bud gets heavily infected the branches will start to die off. The spring is the time when this is normally noticed – too late – then you will have to remove dead branches. I am writing this whilst waiting for my son in a car park in Worthing looking at a London Plane that has shed about 20% of its foliage due to the dry weather. There is also a Norway Maple that has lost all of its top growth. We need rain.
Tim Teear – Arundel Arboretum
