Discovered Some Strange White Blobs On Hydrangea Stems

Question

These white blobs found on my old hydrangeas. They have always flowered well every year and not had any problems. These white blobs are on the stems only, as far as I can tell, and have the appearance of popcorn – white with a brownish centre, and seem to have a similar spongy texture.

Answer 1

Hard to say without pictures but it may be cottony scale or mealy bugs. You can prune off heavily infested twigs and branches, if practical. Biological controls for scale: predatory lady beetles, lacewings, parasitic wasps. If ants are abundant, selectively control them as ants want the honeydew and may protect the scale insects from predators. You can spray horticultural oils and insecticidal soaps. More info: https://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html A friend once told me that he applied a systemic insecticide called Safari 20 SG (active ingredient: dinotefuran) twice a year (at the right time) AND for 2-3 years in a row to get complete freedom. Do not apply Safari if the plant is dormant or the soil has frozen.