Thank you for your question, Janice.  Browning of rhododendron leaf tips can be caused by several factors, including bad drainage, too little water, the scorching of leaves due to (inadvertent) herbicide exposure, and leaf burn caused by full sun exposure.  There are also fungal and bacterial diseases that cause this.  A lack of blooms can be caused by improper pruning and inadequate nutrients in the soil.  I cannot diagnose which of these are at play without knowing more about the plant's placement and care.  Could you please provide more information about water, fertilization, pruning and its site?  Thank you.

Thank you.  Rhododendrons are understory plants in nature, so prefer shade.  They have shallow root systems, and need water at the roots, not on the leaves.  (True for all landscape plants.)  In fact, water on the leaves may cause more severe burning.  The mulch helps to keep the soil moist and cool, but must allow water to penetrate, so needs to be chips, rather than dust.  Without supplemental fertilizer, the plants cannot photosynthesize as well.  And, in order to keep from becoming leggy, regular pruning is needed.  So, you have many abiotic (environmental) issues to address to get your shrubs back in shape before testing for diseases.  Here is an Extension article on this topic that you might find helpful:  https://catalog.extension.oregonstate.edu/fs12/html

Here is an article on pruning:  https://www.extension.purdue.edu/extmedia/HO/HO-4-W.pdf

Good luck!

You're most welcome!  If, after all your efforts this year, your plant(s) still show these issues, you can contact the OSU Plant Clinic to see if there are non-biotic factors involved:  https://bpp.oregonstate.edu/plant-clinic

It will take time and effort to renovate them, and severe pruning will make them look pretty bad at first. Just don't prune below a growth node, or they won't grow back.  It promises to be a very dry summer, so get some soaker hoses, large mulch, and fertilizer for rhododendrons, which need acidic soil.  They didn't get this way overnight, and it will take many nights to get them back to good health (and looks)!

Happy to help!