Choosing a specific cultivar plays a much bigger role in success or failure than time of year planted, or pretty much any other factor, in my experience (IME). For example, as Incantation passed the end of its first full calendar year in my garden in May, it approached nearly two inches across and one inch high. Knowing it was a Barden rose and subject to slow going, I had planted it in a spot where it would get my full attention. That means it was always kept well watered and fed. I pronounced it dead in May, but then in late June when nighttime temperatures regularly got above 75F it started setting new leaves, each larger than a grain of rice but smaller than a black bean. It has since grown.. not a whit. This spring I dug up and moved a Sheila's Perfume that had been languishing in the shade of a Blush Noisette for five years - ever since the day they were both planted in that location, about three feet apart. It was still twelve inches high, as it was when I planted it six years ago. This year, with more light, it grew a second branch and it remains twelve inches tall. But I now have reason to believe that in six more years it might exceed twelve inches in height.
Twelve feet or twenty feet away from these two roses, Mme Alfred Carriere - planted a year or two after Sheila's Perfume - zoomed to eight feet in height in its first summer. Each year I remove from it ten or a hundred times as much plant material as has ever been in Incantation and Sheila's Perfume together. I dig up and move an Ascot almost every year in spring. Each one is set back a bit by the move, but overall, they all just keep on going. This cultivar so robust I almost seek out places where roses do not grow as a new location for a newly moved Ascot. Caramella FT grows a little more slowly but it is definitely vigorous. Ditto Pomponella FT. IMO, the hybrid vigor of Constance Spry, while alloyed with other factors, can be found in many of the David Austin cultivars: Graham Thomas, Teasing Georgia, Lady of Shallott. They can also endure tough conditions, a trait I find to be more pronounced in Portlandia and The Impressionist.
I'd like to use these examples to introduce a new subject.
IMO, there are two important properties of roses that rosomanes tend not to talk about quite enough: Vigor, and Persistence. Most of the really good printed rose references I have read mention vigor. No online reference I've found treats vigor with adequate rigor. In fact, I'm unaware of any that treats it at all. Vigor expresses how willing a rose is to grow under reasonably favorable conditions. A vigorous rose grows faster than one that is not vigorous over a range of generally favorable conditions. It's a well established idea. Sheila's Perfume and Incantation lack vigor. Mme Alfred Carriere and Constance SPry have vigor.
Persistence is a term I have never seen applied to roses. But some roses persist. The idea is related to how well a rose survives a range of difficult condtions such as frost, drought, poor soil, shade, hot weather, low humidity, cool nights, and so on. Sheila's Perfume is a perfect example of a rose with persistence but not vigor. Another is Judy Garland which behaves in my garden precisely as does Sheila's Perfume. It has never grown to three inches tall. It makes a single blossom each year. Then it disappears. Definitely not vigorous. Definitely persistent. (One could use the term hardiness. But the problem is that common usage of 'hardiness' refers only to cold hardiness. Specifically it refers to the coldest temperature that a cultivar can endure for some hours -- to be consistent with the USDA cold hardiness map. Cold hardiness is an essential element in persistence. But so is resistance to late spring frosts, another sort of cold hardiness. And so are a lot of things unrelated to cold weather.)
While vigor and persistence may be correlated in roses, they are definitely distinct, independent properties. In fact, sometimes roses that are too profoundly vigorous will overcommit to good conditions and fail quickly, gloriously, completely - like a car driving full speed into a granite rockface. I saw this happen with a precocious Playboy that set early new growth very quickly and vigorously and was dead a week later from an hour of light frost. Playboy lacked an element of persistence. In contrast, I would say Rise 'n' Shine has persistence. It tends to shut down in many ways whenever conditions verge on the challenging. The plant requires completely perfect conditions to bloom generously. But it survives (moderate amounts of) all sorts of abuse by pulling back and shutting down.
The best roses, especially for gardens not in the Mediterranean and Maritime climate zones, will be ones that have adequate vigor and persistence in addition to their disease resistance, habits, flower characterists, and so on. I believe that one of the reasons many Kordes roses find success stateside is that they, unlike many roses bred in California, have been bred and selected to be vigorous (in addition to being blackspot resistant and cold hardy.) Vigor and persistence are not accidental properties of a Kordes cultivar. It's true, too, of the landscape roses from Meilland. In my experience, some of the Canadian Explorer roses are a little light on the vigor side, but they tend to be quite persistent, some of them.
Seeing that Sheila's Perfume and Judy Garland are both Harkness roses and seem to be distinctive in their persistence and lack of vigor, I'd be very interested in knowing if anyone could suggest why this combination of characteristics shows up so prominently in this breeding house. Or maybe my experience with these roses is unique.
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What follows was originally the first part of the post. It is what led Steve to launch into long musings about rose vigor and persistence, now the subject of the thread ...
I agree with you Sharlene, storage can be a big problem. I lost three of thirty roses from being stored badly in one bare root shipment this spring. Despite daily watering their canes turned brown. Weak growth at the bud union was then nibbled by the garden rabbit. And they were goners. At least four more lost all their canes before growth from the bud union took over. And all but three of the remainder were materially set back by desiccation. It was easy to tell at planting time: they were light for there size and some had wrinkled or browned canes. I cannot say for sure whether it was seven of thirty or twenty seven of thirty that were materially harmed by storage, but my impulse is to say it was 27 of 30.
If my memory serves me correctly, I have had close to 100% loss rate with own root roses ordered in late summer and planted after September 15th. (This may be an incorrect impression for a few multiflora hybrids, but I'm pretty sure it holds for just about every hybrid tea rose.) I think that roses here tend to be caught off guard by fall frosts more than they were in NJ. And I think it's because daytime temperatures can easily be in the mid or high seventies on nights with frost here, whereas in NJ it was more common to have two or three weeks with daytime temps in the fifties before frosts. Also, further north the number of daylight hours changes more profoundly through the year than it does at this latitude. I expect that this gentle slide into winter might be even more prominent in parts of Western Europe than it was on the US east coast. Certainly the change in daylight hours is more profound.
I'm hoping that a full growing season with high diurnal temperature swings (cool nights nights and warm days) will temper the roses now growing in pots so that they are not quite so greenhouse-soft as ones that fall off the truck in late September. I will find out a little more next year because I have nearly a dozen that have been growing in pots since spring that will be going into the ground one at a time between now and, say, mid February - as I make room for them. It's not a strictly controlled experiment, but it may give me a little more anecdotal information. I am trying to keep the pots from overheating in the February sun and intend to move the plants into part shade or else get the plants into the ground before overheated roots prompt vigorous early growth.
My hypothesis is that new early fall arrivals are not appropriately hardened off for the kind of fall weather we have here. If a large portion of the potted roses I plant this fall/winter/spring survive, it provide good evidence in support of this lack-of-hardening idea.
I'm not aware of any bare root rose suppliers in the US that ship outside the traditional spring window (which for me is April 12th to 24th for bare root roses.)
Choosing a the right time of year to plant a rose in a particular climate can be of crucial importance, but...
--- Edited to move the background information below the dashed line, add a few more examples, and add the idea of daylight hour variations/latitude ---
