My rhodies look exactly the same. We've never pruned them. They are all natural and we didn't plant them....they chose where they wanted to grow. Or rather Mother Nature did. We've never disturbed them sprayed around them or done anything to change their environment. Several years ago, they were florabund, but last 2 years, this is all we've gotten. (same as your photo) However; the mountain laurel and the native flame azaela have gone crazy blooming this year and they thrive under the same exact conditions. It's a real mystery. The only thing I can think of is that the plants have gotten "too mature" or the trees around them have and are leeching the nutrients. We are talking about 100-200 rhododendrons on our property and all have the same problem. Yet, the ones just a few feet less elevation on our same road are blooming beautifully.

The wall doesn't look solid enough to me to retain a bed for either a tree or shrub. Also the soil is mounded up in away that is likely to wash out in future. Are you intending to improve the structure before planting? If not I think you'll be fighting a collapsing bed in due course. .

The picture above is of Rhododendron viriosum. Lochiae has curved corollas. I have grown viriosum seed and it is painfully slow - 1 leaf per 6 months. Not worth the wait when you can grow from large cuttings and have a plant in one year.

@luis_pr: My plant does have flower buds, and I will try to take photos and post them here. Pam, Please come down here and explain to my 'Crater Lake' that all rhodies work great here, or I fear it might be dead soon! It has fewer leaves every year and barely grows. I've been blaming the dreadful, hard-packed clay in that particular spot. If it doesn't improve this spring I will dig it up, fill in the hole, place the root-mass on top of the clay, and cover with mulch. Perhaps that will be more to its liking.