Yellowing, then dropping of oldest leaves is normal for rhododendrons, a natural part of the yearly growth cycle. Most evergreens will naturally drop their older needles or leaves (closest to the trunk) after a number of years, making the term "evergreen" plant misleading :) Leaf drop usually occurs in the summer or early fall when the leaves are approx three years old. This period of leaf drop occurs following the maturing of the current season's growth - it's nothing for you to be concerned about.

Improving the mulch is a great idea, will help to conserve moisture and keep roots cool. You're right to water during the dry periods too. Those two things are really all you need to do if the dropping leaves were the only symptom concerning you.

Thanks so much for the reassurance. Yes, otherwise it seems happy.

I am wondering if any of my rhododendrons will ever bloom. It is almost October and some of my plants have big buds that are trying to open? Are these just leaf buds? Both of these (english roseum species) did not bloom this spring, otherwise they look very healthy. Any thoughts on why they are behaving so weird? If these buds are trying to open now, the couldn't possibly bloom in the spring right? Thanks for any help you might be able to give me.

They are flower buds, but it's not clear if they are about to open - the kind of "fringe" at the apex of the buds does not necessarily mean bloom is imminent. If they do, you are correct that it will mean no bloom next spring from those that open.

Some rhododendrons - lots of red flowered ones especially - are prone to incomplete fall bloom. This tends to happen when a dry spell is followed by a wet one late in the summer. English Roseum is not, as far as I know, prone to this behavior. The very early spring and other weather oddities in many parts of the country may account for what's happening if they do indeed bloom.

Thank You so much for responding to my post. We have had an extreme dry period of about 3 months. It's the oddest thing, I have two of these english roseums planted about 15 feet from one another. One looks like its buds are unfolding and the other just as tight as can be. Can "fringing" be caused by any kind of pests?

No pest involvement in the "fringe". Some rhododendron varieties - 'Vulcan' is one - show this on nearly all flower buds. Others only occasionally. I really have no explanation for its appearance on just one English Roseum.