Hi gardeners,
I was hoping you can help me ID this white stuff on my rhoddies and suggest tips for saving the plants. The house I moved into came with a few new plants in my front yard and they were doing great in the wet and long spring we had in the PNW (Zone 8b), but recently one of them is clearly dying with white stuff on the new growth, and the other two are also starting to get the white stuff on their new leaves as well. They almost look like tiny spiders? I sprayed them with diluted neem oil the other night but the white things are still there. Some branches around the outer edges have turned black and dried up, so I've been pruning those dead branches but it doesn't seem to be helping very much. Also, I think it's worth mentioning that the browning on the more developed leaves in the photos came from the heat wave we just had for two days. Any tips or suggestions will be appreciated. TYIA!

Quite possibly aphids. Those white things are discarded skins which they shed as they grow.
They have a life cycle that is measured in weeks. But when the population is big, they suck the juice, the life, right out of new growth. If there are a lot of them they can kill tender new shoots.

No matter what you spray, it must be 100% coverage. Tops of leaves, bottom of leaves etc. If you miss spots they survive and the population continues to explode.