I am starting this thread as a follow up to the niche markets post.
Attached are two old but interesting articles about finding a better rootstock. While rootstock is not a glamorous project, I suspect that anyone who creates a superior cultivar could patent it and make a some money.
Judging from these articles, one objective might be to breed a rootstock that is good for nursery growers AND the average garden. This does not appear to be the case at present.
“Average garden” doesn’t really exist. What’s perfect for an arid, hot, alkaline soil and climate isn’t necessarily suitable for colder, wetter, more acidic types and vice versa. That’s why we have the perennial “Huey v. multiflora” debate. Add the benefits of Fortuniana for sandy, nematode soils and it makes it even more difficult. Huey is better for western growers (where the majority of the production has historically been) and western gardeners (where the lion’s share of plants have been sold for many years), so what you suggest is what has been for a number of decades. Now more production is switching to colder zones, the product may begin increasingly shifting to favoring the colder, multiflora type customers and growers. There was a thread on Garden Web last summer about that question. Some links were shared which stated Huey actually secretes acidifiers into its root zone, helping to alleviate the alkalinity, enabling it to avoid the chlorosis issues multiflora experiences in those soils. Multiflora doesn’t acidify its root zone area.
I sure agree it would be nice to have better rootstocks based on region. At least in my area it is challenging to basically mainly have Dr. Huey grafted roses to choose from. The bud unions swell over time on most rose / Dr. Huey combos indicating longer term graft incompatibility and the accumulation and lack of free flow of photosynthates to the rootstock. Grafting is like creating an arranged marriage and some members can take more than they give and in this case hoard the “sugary goodies”. Over time sections of the excessively swollen bud union dies out and the health of a lot of roses declines. The R. multiflora we often can get seems to have generally less of that issue. Dr. Huey does grow fast initially and gives growers larger plants which is nice for sales.
Dr. Buck bred a number of thornless multiflora rootstocks and they differed in root architecture and other traits. With field production now in generally just CA and AZ (Texas is almost zero, but they still have the old packaging plants there that many roses from AZ and CA get shipped to and distributed from) that provides a bottleneck. It makes sense for them to grow what they are accustomed to, etc. It will have to be some exceptional rootstock to convince them to justify the cost of doing something different, especially if they have to pay a fee to use it.
At the International Symposium on Rose Research and Cultivation in Germany this past summer Jan Karlik and Brent Pemberton presented data on rose sales trends over time in the US. Field production of roses is greatly declining as well as grafted roses. Own-root even hybrid teas is what the market is moving towards (there still are of course grafted ones and will likely be some as time goes by). New varieties that do not do well own root become less valuable to producers. Land prices increasingly prohibit justifying field rose production, especially in CA. Paying for and having a well trained budding crew when one is needed is increasingly challenging too. If roses can be produced own root and never see the field and can be finished in a year or so in a #2 pot that alleviates some bottlenecks. Nurseries like Greenheart and Spring Meadow sell liners and control the royalties from their propagation facilities and regional nurseries finish and distribute the finished plants. From Karlik and Pemberton’s data about 80% of all roses sold to the public are containerized and 20% bareroot. The containerized roses include 60% of those roses never seeing the field and just started and finished in containers. Twenty percent of the remaining roses are own root field grown roses and the remaining 20% of containerized roses field grown grafted roses potted up.
I have a really vigorous R. eglanteria hybrid that surprisingly roots readily from cuttings and tried to have it tested as a rootstock. In the US there is a preference for clonal rootstock versus relatively uniform seedling rootstock as in Europe. Unfortunately, with the market constraints and direction in recent years, it hasn’t really moved forward. I should push harder for it to be trialed as a tree rose rootstock.
Even if there are commercial barriers for us to get new rootstocks into production, it doesn’t mean we shouldn’t work towards that goal for our own benefit and to share good regionally adapted rootstocks with our friends. There is an effort going on to develop a Dr. Huey resistant to crown gall through genetic transformation. It will be interesting how the regulatory agencies and consumers accept that if it becomes commercialized. It could help reduce the use of toxic soil fumigants between rose crops where crown gall has been present.
Good comment there David, when I was in China, they spoke extensively about using own root cultivation. The thing about it though , one would have to reassess the parents as a means of producing offspring which would root with ease and still have appealing qualities to the public.
A rootstock I use here in Australia is Rosa indica major, it has better resistance to nematodes and saline/alkaline conditions than mutiflora.
What we call Odorata over here, Warren. Prior to Huey, Odorata was THE most commonly found rose all over California. Every old cemetery, abandoned home site or old garden contained many. It’s as immortal here as Huey. It also suckers like Bermuda grass…
Something that does very well in most places (cold,hot,dry,humid,acid,alkaline), is vigorous, pushes many blooms, and is easy to propagate, something like Darlow’s Enigma, crossed with an existing stock like Dr. Huey may give good results. DE seedlings do make a lot of basals, so that would have to be selected against, but then we are hybridizers, so selecting certain seedlings is kind of what we do. Just a thought. Most of us seem to be going own root, but a better rootstock is still a useful project to do.
Note: Kind of funny that the forum spell checker thinks the word hybridizer is misspelled.
Perhaps the Rosa Bhutan species rose might be a candidate for a new root stock, as it hasn’t suckered and is very vigorous. I had planted it in a 1-1/2 ft high raised box with the bottom shielded, and it has burst out the side of the box, with a tap root of over 1-1/2" in diameter and plunged down into the soil below. It is disease and pest free and has been over 13 ft high. What other characteristic are looked for in a good rootstock candidate?
Compatibility with a wide variety of scions, for one. Judge Henry Fonda, who lived in Mar Vista by Santa Monica, operated a small nursery at his home for some years. He had an enormous Cl. Cecile Brunner which produced impressive, thick, long whips each year. He tried for many years to root and bud them for use as standard trunks. They’d root but they rejected every scion he put on them. It wasn’t an issue of his budding inexperience as he successfully budded many other roses. Cecile appeared to either be incompatible with anything put on her, or perhaps she was virused or something, resulting in rejection? Who knows? But, compatibility would be a huge factor.
Tens of years ago a few odorata x multiflora inermis rootstocks failed as considered to have not so easy to lift bark.
Moore’s South African OGR is one Ralph Moore brought back from South Africa years ago. He said he thought it might make a great stock due to the long, straight, strong, nearly prickle-free canes it produced. He found he couldn’t lift the bark at all, so it failed for that use.