Rhododendrons at Redwood best time to visit?

Thinking of heading up along the West Coast this year and was wondering what time of year are the rhododendrons normally around at the Redwood National Park and other places along the coast. Thanks for your help in advance.

Early to late May in the National Park. Depends somewhat on the elevation and seasonal conditions.

.....further north into June. I don't know about other areas, but here the rhodies coincide with the beargrass bloos, which can be wonderful. I gather it's not that way further north, some Washington photographers were really surprised to see both in blossom at the same time in an image.....