Rhododendron flower buds are very distinctive - large and shaped like a tight pine cone or the dome of a Russian Orthodox church. (Azalea buds are similar, but usually smaller) Deer absolutely love them, so that may be your problem. Notched leaves usually indicate damage from vine weevils, but may also be from deer. Lots of high winds with low temperatures last winter in the northeast led to a great deal of winterburn. Nova Zembla is rated as very hardy, but in my experience suffers from windburn more than many other varieties. Gibraltar is a deciduous azalea so loses its leaves each fall even though it sets flower buds at that time. If you see evidence of deer eating them, that's the most likely reason the buds have been lost. Phosphorous is unlikely to do any good unless a soil test shows a need. A light application of Hollytone or another complete fertilizer made for acid loving plants may help the plants grow. The number one reason for problems with rhododendrons is failure to loosen the rootball when planting and/or failing to make sure the rootball is sufficiently damp. If you put them directly into the ground without doing these things, it's easy enough to dig them up and replant. There are spray products which allegedly (I'm pretty much a skeptic when it comes to hungry deer) protect plants from them.

Most variegated azaleas/rhododendrons are prone to reversion. That is, stronger growing non-variegated branches frequently appear. In time, they tend to overwhelm the variegated parts. If you wish to insure a variegated fuure for this plant, you should prune out the branches with plain green leaves. The plain green portions probably bloom better because they contain more chlorophyll and naturally do better. Variegated forms can burn in intense sun - although this is less of a problem in Z5 than in warmer climates - so moving this plant may do more harm than good. Poor bloom in evergreen azaleas of all kinds is nearly always a result of winter cold. Z5 is very difficult for most evergreen azaleas. This past spring has been particularly tough as well because of extreme temperature swings which damaged buds that made it through the winter. Neem oil is unlikely to do anything against leaf galls - you're doing the best thing by picking them off and disposing of them.

Some rhododendrons and azaleas are more prone to fall blooming than others. Cunningham's White and Cunningham's Blush are two that frequently do this. Other varieties do it only when the weather, temperature and rainfall patterns are just right. Usually the fall flowers are at least partially distorted and not as striking as the spring ones. Fall bloom does diminish the spring show but not in a very significant way. One caution: "shots of general plant fertilizer" can be harmful, especially fast acting ones applied after the end of June. They can stimulate late vegetative growth which will not have time to harden properly before cold weather. A small amount of Hollytone in the spring is fine and all rhododendrons and azaleas need unless a soil test indicates otherwise.

This past winter was the most difficult I've experienced in what is now close to 40 years of growing rhododendrons. Large rhododendrons, some of which were planted at least 30 years ago, were very badly damaged and some, including two large Percy Wisemans, appear to have been killed outright. The 2018-2019 winter followed another very hot and dry summer, so rhodendrons were first stressed by that despite attempts to provide enough water. Then we experienced unusually cold temperatures in November before rhododendrons had fully hardened off. Almost every snow storm ended up turning to rain which then froze into solid ice which does not provide the insulation of snow. Heavy wet snow and ice also collapsed many fabric shelters. Temperatures also fluctuated dramatically from near 0 to well above freezing time and time again. By far the most damaging aspect, however, was the repeated instances of unusually high winds. As for the photographs: The bottom photo of Percy Wiseman shows in the upper right area the tightly curled leaves I'm seeing in a great many varieties. Sometimes in the entire plant - even in such usually rock hardy ones as Calsap and English Roseum - or in smaller areas. These branches are dead and will not recover unless some kind of Rhododendron Miracle occurs. Cherry Cheesecake is a notoriously difficult variety - the last of mine is a goner - but the one shown is clearly alive. The problem when large parts of a rhododendron have brown leaves and/or ones that cannot uncurl, is that they cannot photosynthesize successfully. A few green normal leaves are, too often, not enough. Plants will linger for a time but then succumb. For the time being, the best thing to do is nothing. It is still cold and there is nothing to be gained by pruning now. It is possible that these plants will recover, so watching and waiting is the best course of action. It is difficult to lose old plants, especially when you don't realistically have 20 years for them to regrow. There have also been exceptions to the general story of damage - 2 Cupcakes, a variety I'm very fond of, are just fine. So is Maricee and Hachman's Eruption even though in the latter case plants on either side are badly damaged. Species, including calophytum, taliense, bathyphylum, adenopodum, sikangense exquisitum, and others are fine. Locations where the wind was less fierce generally did better, but not always. In some cases not even fabric shelter prevented serious damage. In the winter of 2017-2018 we experienced several consecutive days of temperatures around -15. This winter we never went below 0. In 2017-2018 there was good snow cover and deep cold did not arrive until late December. There was very little damage. Wind, timing of cold's arrival are factors at least as important actual air temperature.