Several customers have asked:

Our plums are carrying large crops of fruit, but suddenly the leaves are turning yellow and dropping but the fruits stay in limbo followed by wasps taking over?

Chris replies:

Are plums paying the price of a good summer? We have received a number of calls about plum trees, carrying large (albeit excessive) crops of fruit, apparently and suddenly becoming stressed with their leaves turning yellow and then dropping followed by their fruits staying in limbo, withering and then wasps taking over. The reason? Dryness at the roots, drying winds over the past few weeks, the tree is simply carrying a fruit overload because of an excellent period of flowering, generous pollination and development. Apart from ensuring the tree has adequate water, there's nothing much you can do. Certainly don't prune the tree at any stage, let Nature take its course and see what happens. Hopefully, simple self-preservation will have kicked in - plants drop their leaves and drop fruit often to save the roots, hopefully this is what has happened with the cases we have seen at the Garden Centre.