It is highly unlikely (as in one chance in a million) that deer are avoiding a particular rhododendron because of its hybrid makeup. When hungry, deer will eat just about any plant material and have become a serious problem in many areas of the country. Rhododendrons are particular favorites, especially the flower buds and tender new growth. The explanation of why one is not eaten probably has to do with a relative abundance of choices - the most palatable are eaten first and if there are a great many of these some will be ignored. If there's a scarcity of food, rest assured the previously untouched will be devoured.

I'm talking about 25 year old Rhododendrons 8to10 feet high,foliage to the ground,in the path of deer,foliage to the ground,and 200 feet away a "mushroom rhododendron".I think the deer in the area have many choices,so they go to their "preferences" first.There is not a guard dog tied to the shrub,it is right on the street curb,so there must be a reason it has not been bothered for many years.I'll take a better look to see if it has flower buds on it.

All of my rhododendrons were deer resistant for about 35 years. Then we had a winter with 1 foot of snow every week for 6 weeks, followed by a winter 2 years later that had 4 feet of snow at one time. All of a sudden only a couple of my rhododendrons were deer resistant. I started using a product sold as deer netting that is similar to bird netting. You have to remove it in the spring or the leaf buds and flower buds that stick through it open and trap the netting on the plant forever. That wasn't a problems since the deer browse was during the winter and stopped before the buds opened.

Then last winter none of my rhododendrons were deer resistant and they even figured out how to get at the plants under the netting. Nothing was safe. My solution now is an 8-foot tall black steel mesh deer fence:

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Notice, the rhododendrons are mushroom shaped. This is the first year for the deer fence.

According to extension services and arboretums, the least bothered rhododendron is hybrid deciduous azalea "Gibraltar" with its striking orange flower. The next least bothered rhododendrons are:

other Deciduous Azaleas
R. carolinianum, Carolina Rhododendron
R. maximum, Rosebay Rhododendron
R. minus, Carolina Rhododendrons

Thanks for the responses.
Rhodyman,that's an interesting experience.I guess for 35 years you must have thought you had the deer thing figured out,like,no biggie,right?

I've come to one conclusion after contending with things at a couple of friends places for several years,and that is...with deer there are no conclusions.In desperation,I guess they can develop a taste for anything,and once they do,it's burned in their DNA to come back to it.You read the conflicting info from people in different places on what they go after and what they don't and you realize there are no answers,just a real rough guideline to go with.And if you throw starvation in there,well forget everything you knew.

Sorry to hear about your problems,kinda takes the fun out of things,right? I guess we are all just one rough winter away from devastation.

I always figured that the deciduous azaleas were a safe alternative.My friend has a Flame Azalea (R calendulaceum) that was probably part of the original foundation planting,as it is about 10 feet tall and quite a specimen.However,if the deer were smart enough to pull a bud off of it in the winter,I'm sure they would clean it yearly.

I'm going to keep an eye on the evergreen Hybrids Rhododendrons this year,maybe I'll post some photos in here if I can,to illustrate why I asked the question in the first place.

BTW,I wasn't able to click anything to get your photos,if you tried to post some.

I planted a deciduous azalea bed in the early spring before they bloomed. They had huge buds ready to spring open. A day or two later I went back and the deer had removed every bud. They thought the deciduous azalea buds were candy. I ended up putting a small deer fence around this bed. Now this bed is inside the big fenced in area and I took first fence down.

All of my rhododendrons are deer resistant, I would go as far as to say deer proof :) I've never known one anywhere close to be even sampled by deer.

But then, I could say the same for azaleas too, if deer just hadn't eaten them down to nubs - one year only and never again. Yet.

We have the blessing of infrequent and brief snow cover, I doubt our deer are every truly hungry. Instead, they present us with surprises with what they will randomly browse on - I'm convinced their tastes change. They will consistently get into roses and raspberry canes, those two need protection here above all else.

I have watched them browse on a laurel next door (causing a significant amount of damage), and so has the owner - she doesn't mind. After all, it's laurel :)

Deer pass on their taste in food to their offspring. The fawns browse with their mother for about a year. When a doe finds a new food source, the deer from that point on will most likely keep that in their diet.

There are so many deer now that the browse line is high enough on traditional food sources that they are constantly looking for food sources. The PA Game Commission actually measures the deer density in Pennsylvania by measuring the height of the browse line on the edge of the forests and in peoples yards.

Lots of our shrubs are becoming mushroom shaped up to the browse line. Arborvitae and other shrubs are especially subject to this.

Free Japanese-style pruning.

There are a number of factors that make deer add new sources of food to their diet:

1) Snow which removes the low and grassy foods, but deer will scratch down to get food. We had this in 1994.

2) Deep snow which reduces the mobility of deer making them eat more in a smaller area. That is what we had in 1996.

3) Deer pressure in which deer exhaust normal sources of food and seek new food sources. This is what we had this past year.

Any of these conditions mill make deer resistant plants into new sources of food. All 3 of these conditions will make almost anything that is green into deer food. This is the true test of what is deer proof.