Over the past few years we have noticed that more Annabelle Hydrangeas in this area are being affected by the Hydrangea Leaftier – a small caterpillar that burrows into the flower buds, emerging in June or July as a moth. The signs of a Leaftier infestation are very obvious – the terminal leaves of the rapidly growing Hydrangea are ‘stitched’ together with silk thread to form a bladder like pouch inside which the pale green caterpillar will be living.
Usually there is only one caterpillar per pouch and it will eat its way through the flower bud, destroying any chance of the bloom developing. If you see these pouches at the top of your Hydrangea bushes, control is simple – open up the leaves and squash the small caterpillar. If you do this, the plant will then continue to develop as normal. If you do not open the leaves, as the plant grows the fused leaves will become more and more distorted as the caterpillar ages and growth and flowers will be affected.