Identifying cultivars

David and I work and volunteer at an historic estate whose grounds are being restored.

The historic time frame of this estate is the late 1880s to 1940. What I have been starting to do is find cultivars of appropriate species which date from prior to 1940. As we replant we want to stay as historically relevant as we can. For instance, there are numerous cultivars of the Norway maple that were introduced during this time frame such as the Schwedlerii and the Accolade elm which is more DED resistant than the true American elm.

So my question is, do any of you know of good resources for determining the dates of introduction of cultivars? Names of books, websites, or anything would be greatly appreciated as I begin work on the Master Plan and suggested tree list for this project.


Up here I would contact the PFRA shelter-belt Centre in Indian Head SK. They are the Federal Tree propagator.

Down your way I wouldn't know who to contact.

Good luck.
Now I am seriously ticked at myself. I came across an on-line book preview (I think it was at that had a ton of cultivars listed alphabetically. Many listing dates of introduction. I got interrupted and cannot find it again.

Now I need a computer geek to help me retrace my steps backwards to find the blasted source again.

A general update:

Through the efforts of Tomthetreeman, who connected me with a highly respected authority, I was given the name and title of a possible book of interest. I was able to obtain a copy of this out-of-print book that perfectly suits my needs.

The reference is Willet N. Wandell's "Handbook of Landscape Tree Cultivars". This book, published in 1989 lists cultivars, their trade name, introducer and, in the majority of cases, the year introduced. It also provides a brief description.

This will prove to be a valuable asset as we develop the arboretum.

Thanks very much, Tom!

My comment in my initial post of the Accolade elm being introduced prior to 1940 was also questioned by this authority, and rightly so. The seed from which this cultivar stemmed was given to the Morton Arboretum by the Arnold Arboretum in the early 1920s; however, the cultivar itself didn't hit commercial introduction until the early 1990s.

As hybrid elm cultivars of the appropriate time period are scarce to say the least, the Accolade elm will still be accepted at the historic estate in question as being a more appropriate selection than the original Siberian elms planted or the true American elms which are so susceptible to DED.

Improved cultivars of appropriate species are not necessarily being shunned from being planted at this arboretum, but we feel it is important to label such additions accurately.



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Glad that worked out, Sylvia. I'm going to look for a copy of that book as well.

Thanks for the brief history of the Accolade. We have some Ulmus X Accolade 'Morton' here in Providence, planted about 3 years ago. I assumed there was a connection to the Morton Arb, but never looked into it. Not sure what makes them different... There's also 'Triumph.' What's the book say?

As hybrid elm cultivars of the appropriate time period are scarce to say the least, the Accolade elm will still be accepted at the historic estate in question as being a more appropriate selection than the original Siberian elms planted or the true American elms which are so susceptible to DED.

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Over here Ulmus pumila has naturalized and replaced the native cottonwoods as the predominant deciduous along some of the main waterways that connect the lakes in our valley (Okanagan). My favorite question from a lady I was discussing this with:

Q: What kind of tree is this?

A: Siberian elm ma'am. Or Ulmus pumila if you prefer botanical names

Q: Is it invasive?

A: Its name implies it's Siberian ma'am...yes!

Good luck with your arboretum, that is my dream to establish jealous
The book doesn't include 'Triumph' so am going to go out on the perverbial limb here and say it was introduced after publication. :)

In addition or in support of that assumption, this link also states that the 'Triumph' parentage is Accolade and Vanguard.

It is "interesting" to note that many of these cultivars have Ulmus pumila rootstock.

And I agree that we need to remember that nonnative is not synonymous with invasive. A plant becomes invasive when it takes over and dominates other desirable species to their detriment. That's my interpretation and I realize this may differ from other viewpoints. The definition of a weed being anything growing where you don't want it to.

I planted 5 Accolade elm trees in my city as street trees this fall as a test to see how they will fair. Before I planted them, I did some research and found that there is no American elm in them at all, nor is there any siberian elm. They are a cross between two different varieties of Ulmus davidiana, an elm native to Asia. So, basically they are an Ulmus davidiana.

Edit: I think 'Triumph' is just a trade name, not technically a seperate cultivar. I could be wrong
The Accolade was developed by the Morton Arboretum from a seed received from Arnold Arboretum in the early 1920s.

Information I have seen lists their parentage as a cross between Ulmus Davidianna var japonica x Ulmus wilsoniana. (Some shorten the Ulmus Davidianna var japonica to simply Ulmus japonica.)

They are promoted (from what I see) as being resistant to both elm yellows and DED with a vase-like form resembling the traditional American elm. I have never heard that they claimed to be from American elm parentage.

Whereas I had heard that Ulmus pumila is used as root stock on many hybrids, I find it interesting that the Colorado site lists the U. pumila under the Triumph as a part of the cross but not the Accolade even though they state the same information that the U. pumila was used as rootstock in both.

I am trying to remember a tidbit of information I was told on the confusion caused by Trade Mark names as opposed to Registered names. That the tree may essentially be the same...just a new introduction. I will try to find that tidbit and pass along if it proves relevant to this discussion.

The tidbit: "many cultivars are renames and the public has no idea. potential to have 2 to 3 dates for the same plant depending in when the plant was renamed."

This certainly gave me comfort when I was getting more and more frustrated about being able to tell cultivars apart...perhaps I am not quite as dense as I thought I was.



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How about this one... 'Vanguard' is U. pumila x U. japonica. When you reverse the pumila and japonica you get 'New Horizon.' ???

I knew you'd chime in, Sylvia, after your research on the Morton. Thanks for the clarification.

"Morton Accolade™ is an elm cultivar derived from a hybrid planted at the Morton Arboretum in 1924, which itself originated as seed collected from a tree at the Arnold Arboretum in Massachusetts. although this tree was originally identified as Ulmus crassifolia, it is now is believed to have been a hybrid of the Japanese Elm Ulmus davidiana var. japonica and Wilson's Elm, the latter now sunk as another form of Ulmus davidiana var. japonica."

What I take away from this is the Accolade you buy at the nursery now, are cultivars of the Morton hybrid planted in 1924 as a seed from the Arnold Arb. taken from what is basically a cross between two variations of Ulmus davidiana var. japonica.
This is about 8-9 years late, but while I'm here...

Accolade(TM) is the trade name for Ulmus davidiana 'Morton'. And, yes, in the early 20s the Arnold Arboretum distributed material to Joy Morton to establish a collection for his new Arboretum. Of this material, a seed of Ulmus davidiana (definitely not U. crassifolia) was planted at the estate.

Fast forward a few decades, and Dr. George Ware was working as a researcher at the Morton. He noticed that after the devastation of Dutch elm disease, a tree very much like the American elm was still healthy and thriving. This tree is what initiated the elm improvement program at Morton, and is what would later be introduced as Accolade(TM) elm. The name in single quotes is the cultivar name, the name ACCOLADE is the trademark name. For more information about trademark names, check out Tony Avent's article here.

In the elm improvement program, Ware used ACCOLADE as a parent for breeding in addition to many other species (e.g. U. pumila). TRIUMPH ('Morton Glossy') was one of the introductions that was produced from this deliberate hybridization. Due to the efforts of Ware to acquire as many diverse elms as possible for his breeding program, the Morton now houses one of the most comprehensive elm collections in the world.

VANGUARD ('Morton Plainsman') is another one of these selections. U. pumila x japonica means that pumila is the female parent and davidiana v. japonica is the male parent. If you reversed it, then japonica would be the female parent and pumila would be the male parent (which is what they did in WI to develop 'New Horizon')

If you purchase an ACCOLADE elm from a nursery today, it is a clone of the original tree that was given to Morton as seed from the Arnold Arboretum. They are propagated through tissue culture and grafting methods. The original ACCOLADE elm is still at the Arboretum growing at the Thornhill Education Center, the remaining wing of the original estate.