Nova Zembla is an island off the northernmost part of Russia, in the arctic regions. I think it has a colloquial meaning of "the end of the world" -- like Siberia. So the rose is very hardy. It is a rugosa hybrid and has beautiful blush (whitish pink) flowers, something like New Dawn, and with a heavenly clove-like scent, inherited from its rugosa parent. It is a sport of Conrad F. Meyer which is slightly darker pink. There used to be several specimens of it in the old Brooklyn Botanic Rose Garden, pruned to within an inch of their lives. To say it is a climber is a pleasant fiction. The truth is less attractive, for Nova Zembla and its parent have some severe drawbacks in their manner of growth. I used to grow this rose, so I know. 1) Even with excellent culture at the BBG, it was not all that floriferous. 2) It has tall stout canes, about the diameter of your fist, armed with thickly-set, truly vicious thorns from top to bottom. The foliage (as I grew it) was not especially attractive, profuse, nor healthy. 3) It blooms only at the very tippy tips of those tree-trunk-like canes. The head of the BBG rose garden in the 1980s was a devote of pruning and he kept his plants to five feet, and fairly presentable. Also, if you live in zone 4 it might not grow as tall. The scent is delicious. So why not try it. If you don't like it you can do what I did and get rid of it. I thought it was a hazard in my small city back yard, after accidentally cutting myself on it more than once. Some of the pics. on Helpmefind also reveal its manner of bloom. The attached one shows the thorns. Here is a link that might be useful: Nova Zembla showing thorns

north side of my garden... Nova Zembla is a 40 year plant.

Those look like bloom buds to me!

The dehydrated cow manure is unlikely to do any harm as these products tend to be very low in nutrients. What is more important is the clay soil. Rhododendrons need a highly organic planting medium that drains rapidly and contains a lot of air space. No matter what you do by way of amendments, it's very hard to achieve those objectives with clay soil. The best solution is planting above the clay in a raised bed. I use partially decomposed soft wood bark as the planting medium, other coarse organic mixtures will work equally well. PJM and Aglo are particularly tough varieties. Spindly growth is usually the result of too little light. Prune back to live wood and pinch the growth tips to make them bushier. If they are in too much shade, moving them is the only real solution. A bit of brown near the bud tips sounds normal - the English Roseums should bloom unless they were subjected to extreme cold and wind.