Stanc, I think the World Federation Of Rose Societies has been debating this question.
I've not followed the debate closely, but I think perhaps Paul Zimmerman has, and perhaps others here.

I worry less about roses which are in commerce than those which are not.
In particular, I worry about some of the unusual, but distinct, found roses that are not in commerce, or which may be in very limited commerce.
Lose one or two more vendors, and we would stand a good chance of losing some rare roses.

One way to help secure these rarities is, of course, for us to grow them -- and to encourage others to grow them.
Another way to help them survive is to do whatever you can to see some of them donated to public rose gardens.
(That's why I loved the idea of sending $$$ to a good vendor to order roses for the San Jose Heritage Rose Garden.)

We have also been propagating some "not-in-commerce" roses for the collection in the Sacramento City Cemetery, and extras for the April rose sale there.

Get involved with a local rose garden -- or local rose clubs, groups, and societies, and you may find other ways to promote less-common-but-valuable roses.

Jeri

As a class, I'd guess the most endagered (in % numbers) are the mini roses. There have been thousands introduced in the past several decades and I'd guess most are gone.

But I'm sure you're asking about the older roses, the ones who're in classes that are already culled by time.

I am in total agreement with Jeri about the found roses. They don't have names that are accepted by the ARS, they don't make it into rose shows except for the few shows that have a special class, their local terroirs (I love that word) are underappreciated.

The found roses I have all survive drought and zone 6 winters.

Were I to try to keep alive Pernetianas, I'd loose my mind. They need different conditions than I have here. They will grow, but they won't thrive.

I have a strain of the china Old Blush that is Zone 6 hardy and probably it's survived zone 5. The rose that Roses Unlimited has "Old Grey Noisette" is superb with an ability to survive drought and live with roots in winter mushy soil with great health.

Roses that need to be grafted onto rootstock to survive, eventually won't. History isn't on their side.

But back to your original question:
(Oversimplified answer) The most endangered are those from the 1800s and early 1900s that survived well in their terroirs, only to fall prey to the advertising driven rose sales of the twentieth century. Those ads convinced people that HTs were the only roses worth having, and so the roses that had given great service were left aside.

In those groups I'd lump the descendants of Double Michigan, the Boursaults that are totally unappreciated at present, and the noisettes in bright colors (red and purple) that have been misplaced for 150 years.

Here is a link that might be useful: A discussion of Terroir

But back to your original question:
(Oversimplified answer) The most endangered are those from the 1800s and early 1900s that survived well in their terroirs,

*** And Ann's excellent reply reminded me of something else.
Many of us here tend to talk about our beloved Teas, Chinas, and Noisettes.
But there are doubtless a good many roses whose terroirs are the more northerly
areas, with colder winters.
The principal remains the same -- the ones that have stubbornly refused to
die, even when not pampered, or even cared-for are the roses that should be
preserved by people in those terroirs.

Jeri

I hope the Ramblers survive, from the Ayreshires, to the Multifloras and all the wiches, and sempervirens, but as more and more of us move to the cities where houses have small lots, few gardeners choose to plant a non-remontant rosebush, that will use up most of their "rose real estate" in their garden.
I've been concerned ever since I noticed our local rose park in Oakland, lost its collection of Rambers. At Morcam park, Ramblers were planted on a hilliside in the 1930's, but by the 1980's the old tall fence they were planted on broke down and was removed, only Alberic Barbier' survives as a bush, whacked back to c. 8 feet tall every year.
- I've grown "Albertine" as a shrub for years, and its' thrived despite being left in a smallish pot that I neglected to water for a couple months during summer drought. It is tough as nails. I've kept it 5-6' tall since I rooted it, c. 7 years ago. I think many other Ramblers may be equally as tough from their species parent genes, and could be grown as 6' tall shrubs in pots to reduce their size from root restriction.
Lux.

Stanc, ultimately that decision rests with you and your choices. I don't think you can be expected to save a rose you find unattractive and possibly lose one you thought was one of the most beautiful. Wouldn't that be tragic!
that being said, if there are roses you really like but are only offered by one vendor, that might be the place to start. If you see a rose you find most attractive, but isn't mentioned in a book, or advertisement, or even on these forums might be another.

I suggest that you research roses that were bred in your area for your area and I am sure that you will find worthwhile roses that are on the verge of extinction. I have done that here on the Canadian Prairies and have been able to make a nice looking (if I may say so myself)garden. I had fun this winter tracking down a rose that was bred by Percy Wright, found it only in the Montreal Botanical Garden and an looking to getting a cutting this summer.
Leo

I'd say the most endangered roses are once-bloomers that haven't made their way into commerce. To a certain extent, if you can buy it, it's reasonably safe.

So, do you know how to root roses?

There is work afoot to conserve roses through the World Federation of Rose Societies. Most of the work is being done in Europe on a country by country basis. For example France is attempting to create gardens and collections for all their rose breeders. Other countries are following suit. The WFRS committee attempts to help by gathering the information in one place so people can cross reference roses or find out where they can obtain roses they are looking to add to their collection.

To give you an idea of how quickly roses can disappear as of the latest WFRS database count the Fineschi garden in Italy has some 800 varieties that to their knowledge are unique to their garden.

IMO it will be a combination of public and private gardens plus nurseries that will keep roses safe. The nurseries can often help by donating time to propagate and exchanging cuttings of the roses in public and private gardens.

The key IMO is gathering information into a central place where others can see it. The internet is a great tool because it allows for a fluid exchange of information. The WFRS database is good for this as is Help Me Find. Rose groups are also a great help to this effort.

And this absolutely includes found roses. After all many of todayÂs OGRs were found roses at one point.

In Descanso Gardens Rosarium there is a sign that indicates that the roses most in danger of disappearing are the early and pre-Peace Hybrid Teas. Possibly this is a tribute to the tender qualities of the early and pre-1945 roses, and possibly it is that attention to these roses has been less than that paid to OGRs, but there are certainly some beautiful roses in that era, especially some of the early Pernetianas. JimD

The whole point originally to OGRs, and particularly found roses, was that they had been selected over the years to do well in areas where the 'modern' roses didn't. Preservation of the older moderns just opens up a minefield of how much we can expect from preservationists, what we really should be preserving, and a whole host of other issues.

For example, if a tender rose is available in very limited commercial supply, should I even be buying it with the understanding that it will probably live only a couple of years in my climate? Is that rose better off somewhere else? Am I better off with a different rare rose that stands a better chance of survival?

Am I better off with a different rare rose that stands a better chance of survival?

*** I think so.
A rose well-suited to your climate, which is rare and/or endangered, could live safely in your garden, and perhaps eventually be placed in commerce.
You can also make an effort to add such roses to public gardens in your area, where people can see them, and covet them.

Jeri

"A rose well-suited to your climate, which is rare and/or endangered, could live safely in your garden, and perhaps eventually be placed in commerce."

Agreed, Jeri. And the same goes for nurseries and public gardens. We have tried many roses here that do not like our climate so we have stopped trying. They should be grown in places where they are happy.

That is why IMO sharing knowledge of who grows what and where is important.

We have tried many roses here that do not like our climate so we have stopped trying. They should be grown in places where they are happy.

*** That's a homely little truth.
No huge heroics to force a rose to grow where it's not suited to flourish.
Take the easier path, for you and for the rose, and grow what is happy where you are.

Jeri

I'm worried about Crimson Glory, my number one favorite rose. It seems to be disappearing from commerce. Only Hortico seems to offer a grafted specimen. The own-root specimens from Roses Unlimited, Vintage, etc don't seem to do as well. I wonder if it has always been grafted or was it own-root when it was introduced in 1935? Does anyone have a source for a budded CG that is not Hortico?

All the Canadian privately hybridized zone 3 prairie roses from 30's onward are always in danger (I mean really zone 3 hardy not these lame federale roses). ... Prairie Peace a real new jewel, Hazeldean, all the Skinner, Percy, Bugnet (except Therese)etc roses. In the states I think you just about lost nearly all the hansen roses or can't decide which one is which anymore.

All suited for here which I think was the point of your question.

Of course personally I also mix through mystic Valkyrie support for my heroic Nordic fatal efforts a dedicated area where I save exotic warm southern European ladies in danger of extinction for my personal pleasure and a change of pace and taste ...

{{gwi:223496}}

I was glad to read the post by jimofshermanoaks, about early HTs. I have a VERY small rose collection (eight roses), and of these, 3 are early HTs: Nigrette, Angels Mateu (a Pernetiana), and Betty. I got them because I fell for their beauty, and also because they are small (small is essential for my little gardening area). But reading Jim's post makes me feel that I am also doing my bit for preservation, and that's a very nice feeling.

Jeri wrote:

"You can also make an effort to add such roses to public gardens in your area, where people can see them, and covet them."

Easier said than done! You'd think public gardens would be open to preserving climate-appropriate old roses that once grew here, but I've been trying to talk a local 19th century home/museum into putting in the kind of 19th century roses that would have originally grown near the homestead but so far have been stymied because there is a garden design committee with, I'm sure, various landscapers and "experts" who probably think more in terms of aesthetics and modern, easy-care plants and may know little and care less about heritage roses. I can see this will take persistence and persuasion...

While it is valuable to incorporate OGRs into the plantings of public gardens and historical remainders, IMO it is even more valuable to have individual gardeners incorporate endangered roses into their own gardens and passalong cuttings whenever asked. The history of public gardens in the U.S. is largely one of disappointment and disappearance either for reasons of 'progress,' especially 'development,' or updating the roses for easier care. Local societies can assist in the preservation of endangered roses by stressing programs of propagation, running the gamut from budding to rooting cuttings. JimD

I know of a Botanical garden that has a rose garden and a test garden and the local rose society has offered to take care of the roses on a volunteer basis,you know free help.
Strange as it may seem they can't do it,something about protecting union jobs.
The things is the people at the botanical gardens always want a volunteer speaker for the "Rose Festival Weekend.

Read that message from JimD, and then read it again.
I wish it weren't true, but having been there and done that, I KNOW he is right on target.

Jeri