Notched leaf edges on rhododedrons are typically a sign of weevil damage - adults eat the leaves and the grubs or larvae can feed off the roots. They can affect various ornamental plants - laurels, hydrangeas, viburnums, gaultheria - but rhodies seem to be at the top of their list. In most cases, it is the adults that do most of the damage but it is entirely cosmetic. The larvae seem to focus more on containerized plants - plants established in the garden seem to be able to deal with any root feeding.

They are difficult to control. First, they are all over. Anywhere there is wood is a potential habitat - wood mulches, wood piles, trees, wooden fences, siding. So removing any adults found in your garden is not necessarily the end of the problem as they will move in from surrounding areas. And you need to kill off the larvae as well. If you want to attempt control, the methodology here is to trap or collect the adults (they are nocturnal, slow moving and can be shaken out of the plants) and use nematodes to kill off the larvae.

Most gardeners here tend to ignore them, primarily because they are so hard to control and because the damage tends only to be cosmetic, with no real threat to the health of the plant. And not all rhodies are affected uniformly - some varieties are much more appealing to weevils than others. And they have nothing to do with the size of the blooms. That is more likely to do with insufficient water during the period the flower buds are developing - late summer into early winter.

Rhododendrons and weevils.