One of the most popular of the cold hardy ironclads, primarily for its large and prolific cherry red trusses.

Some idiot on youtube was calling this root rot resistant a few years ago. It is most definitely not. In a scientific study a few years ago, it was ranked moderately susceptible. The ever useful Cox Encyclopedia also notes it is prone to rot in "some areas of the SE US". So, not as bad as some, but still enough to warrant concern in Cairo, IL. Your summers are very hot and humid.

I'm not saying to panic, just to be aware of the issue. If you've already bought the plant, that is...

I'd grow 'Francesca' if I wanted a very solid zone 6 hardy red...and 'Vulcan' if I wanted to be a little adventurous. 'Vulcan' might get burnt some winters, but both have vastly better red flowers. There are other lesser known cultivars as well. In my opinion, there's seldom any reason for someone who really cares about the genus, to be growing those old 'ironclads' anymore. Sure, they are fine for landscaping funeral homes and gas stations, but home gardeners can do better.

David, in zone 6 one's options are sorely limited.........few cultivars other than the ironclads will be reliably hardy and flower well :-) I would consider Vulcan to be very marginal in that climate.

And I would have to say that few posters to this forum share your interest and enthusiasm for this genus. Most are just looking for a variety that will grow well and bloom reliably in their garden. Maybe home gardeners can do better but very few care enough to :-))

Ok, Vulcan has been 100% hardy here even in the 3 "bad" winters, when even other "zone 6" rated plants showed damage. It's not like I recommended 'Leo' or 'Captain Jack' - both of which are still surprisingly hardy given their parentage. Cox rates it hardy to -10F; 'Vulcan's Flame' is rated even hardier, -15F, by him, and he gathered information from A LOT of correspondents in the central and eastern US. I might have preferred to recommend that one ('Vulcan's Flame'), but I'm still not going to back down on my assertion that there absolutely have to be better reds for the warmest, southern tip of IL. I couldn't remember the name but now recall seeing 'Henry's Red' at Rarefind (I think) that is rated to -25F! And yes, it was a better red too...almost anything is than the muddy, deep cerise-pink of 'Nova Zembla'. Rhodies are clearly one of my fav. genus, but I also think some of them have the most vile colors I know of in the world of plants!

I think you raise a philosophical point, well, why IS anybody here? If we are going to just recommend only the plants people can find at HD & Lowes, why bother? When I started gardening I certain wish I'd gotten advice to ignore or discount things, that I later discounted myself! 'Francesca' is available now, as are the others, from various mail order nurseries, that could use the business. That being said if 'Nova Zembla' looks beautiful to the OP, by all means, plant it. I'm sure as far 'north' as the suburbs of DC, I've seen more than one clearly dying of root rot. So I'd recommend being very careful how to plant it in a place with summers just as hot. I didn't go into it, but based on my 'Vulcan' never flinching a bit in hot summers, I'd also suspect it's more heat-resistant than 'NZ'. Of course it's hard to fully compare because I follow more sensible cultural practices than some people. Maybe the dying 'NZ's (and other 'ironclads') I've seen down in DC, had earlier had some idiot dump a bunch of fertilizer on them.

Anyhow, back to the philosophical point...I will go on recommending along the lines of "I think the best answer" or "what you don't know about, that might be better than what you do". etc. etc. because that's the advice I'd want. Golden rule and all haha.

David, in zone 6 one's options are sorely limited.........few cultivars
other than the ironclads will be reliably hardy and flower well :-)

FWIW, this is really not true. Rarefind was technically in zone 6 and had hundreds of cultivars on-site in its heyday. But an even better example is the Holden Arboretum...really zone 6, and many many cultivars beyond the mostly-boring and outdated 'ironclads'.

I don't recognize that name. It's a lot easier to find a white, hardy, rhododendron than most other colors. White and pink are kind of the 'default' of the genus. Rhodyman had a thread a few years ago about his opinions on various whites.

Why bother?? Because that is often exactly what people want!! This topic has been brushed on before (not necessarily on this forum) and the conclusion is that serious hobby gardening is becoming a bit of a dying art with many posters here not at all interested in anything particularly unique or out of the ordinary and are only looking for easy to obtain reliability :-)) And the Lowe's and Home Depots of the world (and the Walmarts, Ace Hardwares, etc.) are what many consider to be your basic plant nurseries.

While you and I may have more far reaching plant interests, we are the exception rather than the rule. And if you don't mind me saying - you, David - have particularly refined and obscure tastes!! I though I knew a lot of uncommon plants but you consistently stump me with stuff I have never heard of before :-) Would that everyone share your passion........but very few do.

Should we make other suggestions? By all means!! But not many are that inclined to experimentation or zone pushing and if it can't be purchased easily at their local box store, it just ain't gonna get planted :-)

Well, yes, I appreciate your POV. But I think most people even bothering to show up here, to ask a question, are smaller, self-selecting group than those who just wander into Lowe's or HD to buy a blob to put by their front door. That may or may not be the case with the OP.

So I gave the big picture, practical advice: watch out, it's not super root-rot resistant...

and...

the esoteric, David mystical advice: find a prettier cultivar, you've only got one life to live and most of us only one or two gardens to plant!

littleegypt was presumably asking about the very common ironclad 'Catawbiense Album'. It's fine. Willl make a pretty shrub. I'd much sooner plant it anywhere than 'Nova Zembla'. OTOH, I go back to the urge to give the "best possible advice". If you no longer need a fancy color like red, and you JUST WANT A RHODODENDRON, by all means, in southernmost Illinois, get a known, super root rot resistant variety. Like the Southern Living Southgates, or non-patented equivalent like 'Charles Loomis'. Then you NEVER have to worry about heat resistance. CL is in almost full sun here, and laughed off the 3 hottest summers since the 1930s (2010,2011,2012). Lesser cultivars nearby were incinerated...

I honestly like the color of Nova Zembla, so don't be put off by David's view on that if you like it. It is a somewhat ungainly plant IME, having more bare branches and less dense foliage than many cultivars, so I do think that you can most likely find a better choice for your zone.

And as far as "there's seldom any reason for someone who really cares about the genus, to be growing those old 'ironclads' anymore", I grow them because I have rather limited choices for my zone. Sure, there are other, more choice rhodies for my zone, but not huge numbers that are available in commerce. Given the amount of space I have available and how much I like rhodies (thanks to many childhood visits to Holden Arb. as well as having grown up less than 5 minutes away from the nursery of a rhodie breeder, Tony Shammarello) I will plant almost any rhodie that is hardy enough for my cold climate.