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What is a rootstock?

Basically, it is any plant used to provide roots to another plant. Lilacs are often grafted on privets to reduce suckering.Specific varieties of fruit trees are used for creating dwarf, semi-dwarf and full-size fruit trees. For example, one can’t reproduce a Valencia orange by planting its seed. Seeds result from sexual reproductions, and as such, the fertilizing of a seed then means there will be a reshuffling of the genes, thus changing the characteristics of the fruit, plants, blooms, etc.Grafting is also a faster way of reproducing a specific variety for commercial sale.

When you root a six-inch cutting, you use several growth buds (bud eyes) to produce a new plant. There have been experiments that have proven it is possible to produce a new plant by rooting one growth bud, but it generally requires more expertise and equipment than the average hobbyist has. By inserting a growth bud under the bark of a growing plant, or grafting a growing stem of the desired variety on another set of roots, a larger, mature plant is produced more quickly than by rooting a cutting. Some plants, such as the lilac and most species roses, can be grown in a garden-worthy form to be enjoyed without the fear of them suckering all over the place. For example, R. Californica, HARRISON’S YELLOW and many old garden roses all sucker badly if not grafted onto some form of rootstock.

R. wichuraiana climber, DR. HUEY. The great American rosarian and hybridist, Captain George C. Thomas Jr. (Captain Thomas) was originally interested in roses and encouraged in his efforts by the well-known, well-respected American rose man, Dr. Robert Huey. To honor his good friend and mentor, Captain Thomas named his break-through climber in Dr. Huey’s memory. A bundle of cuttings from his climber reportedly became confused with those of GLORIE DES ROSOMANES, commonly known as RAGGED ROBIN, in the Armstrong Roses growing fields. Since it wasn’t really possible to tell the difference until the roses bloomed, (RAGGED ROBIN was used extensively as a root stock), this mistake proved the great value of DR. HUEY as a rootstock.

The vast majority of commercial bareroot roses produced in the United States are grown on DR. HUEY. It has been used by Armstrong, Jackson & Perkins and just about all of the other major rose growers. Its main benefits are that it is nearly universally compatible with most rose varieties; it’s quite cold hardy; it’s fairly easy to root; its bark lifts relatively easily; it grows well in most soil types and climates; and it is the least likely to reject an inserted bud because of water stress. DR. HUEY has also been called SHAFTER, named after the community along Highway 99, north of Bakersfield, near Wasco, where so many of our roses are grown.

R. Multiflora is a very popular choice for amateurs as well as quite a few smaller and foreign rose growers.Since it is a species, it is often grown from seed to be used by commercial growers, particular in Canada and Britain. It is available as seedlings from several growers.I have found it the easiest to root and its bark lifts very easily for an inserted bud.R. Multiflora is available in many forms, including several that are completely thornless, which makes it extremely easy to use. It is so vigorous that it provides a big “push” for the budded variety.I like using it for those roses that won’t produce vigorous plants, forcing them to yield more propagating material in a shorter time.However, it is more susceptible to chlorosis than DR. HUEY, so more care should be taken to assure that the requirements preventing the problem are provided.I find that many violet colored roses grown on R. Multiflora need frequent applications of iron, s many of them have inherent chlorosis problems of their own.

As a rootstock, R.odorata is used by few domestic commercial growers.It is more difficult to root; seems to be very susceptible to bud failure due to water stress; and has a narrower range of soil types it will grow well in.Dr. J. H. Nicholas wrote in his book, Rose Odyssey, that R. Odorata produces more controlled growth with far superior blooms, especially for varieties descended from R. Foetida.Tom Liggett (in San Jose) agrees that the Odorata-based plants develop into better bushes with more perfect blooms, and wanted to use only this stock for his bareroots.Unfortunately, Tom found that the bud failure rate was too severe, so he now uses DR. HUEY extensively as it yields substantially greater success.

FORTUNIANA, supposedly a R. banksiae and R. Laevigata cross, is used by a few specialty nurseries in the southeast, most notably, Florida.It reportedly is more adapted to the sandy, wet soil predominating in that region.I understand it may be more resistant to nematode problems that are more prevalent on sandy soils.While it might be better for the very deep south, it doesn’t perform well in heavier soils; isn’t compatible with as many rose varieties as the preceding types; and isn’t dependably cold-hardy.This one is probably better left for Florida rose growers.

MANETII is a noisette from about 1835 that has been widely used.It isn’t very cold-hardy, and develops a characteristic known as “carrot-root.”It forms a large taproot shaped like a long, thick carrot with far fewer side roots than the others.While it may grow well and produce pretty plants, MANETII will be more easily toppled by wind as it has greatly reduced vertical stability.MANETII has been used for years as the understock for greenhouse roses, where it performs well since it likes warm soil, and the glass houses protect it from the wind.

I.X.L.R. is a hybrid Multiflora rambler that produces a wealth of long, straight, thornless canes, often an inch in diameter.It was used for many years as the trunks for tree roses because of its ability to give its strong, large canes in one season.It roots easily; is compatible with many roses; is easy to bud as the bark lifts easily; plus it is very vigorous and produces fast growth.Its drawbacks are that it is quite susceptible to water stress leading to bud failure; being a Multiflora, it becomes chlorotic more easily; and the bark sunburns more easily than that of DR. HUEY.I.X.L.R. requires a lot of room to produce plants yielding canes the size used for trees roses, and land prices are high, so it is rapidly being replaced by DR. HUEY.DR. HUEY works well, but the trunks aren’t as long or thick.VEILCHENBLAU and TAUSENDSHON, both hybrid Multifloras, have also been used as rootstocks.

R.Rugosa has been, and occasionally is used for bush and some tree roses, and is mentioned for this purpose in many old rose books.It will bud, and it roots quite easily, but it suckers all over the place and is really not suitable for a rootstock in my opinion.It’s also extremely thorny so is no fun to work with.It has recently been used for tree roses by Hortico, with the expected results.EGLANTINE (SWEETBRIAR) has been written about as a rootstock in old books, and has also been used recently by Hortico.It roots and is very cold-hardy.It also suckers badly and its prickles make it almost as painful to work with as R. Rugosa.

R. Canina has been used for decades in the British Isles and in Europe.It may be a perfect choice for their climate and soil as it is indigenous to the area.It, along with Multiflora,  is grown from cuttings and seeds by the Dutch and others for use all over Europe.Harkness, LeGrice, McGredy andWheatcroft, to name a few, have written of visiting the hedgerows to collect the naturally occurring seedlings of R. Canina for this use.It is hardy and roots was well as any other.My experience is that it isn’t very happy in our heavy clay soils.Imports grown on the original R. Canina rootstocks compared with plants I’ve budded from them on Multiflora, DR. HUEY, and I.X.L.R. have never developed to as high a level as my budded plants have.It is probably best left to those growing roses in a northern European type of climate.

Actually, just about any rose which roots easily, whose bark is easy to lift from the cambium layer, and whose wood is long-lived should provide all you would need for a suitable rootstock.More modern roses such as hybrid teas and floribundas who need to regenerate themselves each year to remain vital, probably won’t be suitable as the wood matures then begins to decline too quickly.You want the roots of your rose to last for years.One exception is the hybrid tea BRIDE’S DREAM.Although Hortico swore it never used it as one, the suckers emanating from the stock under Bill Grant’s Hortico-grown Austin roses were definitely BRIDE’S DREAM.

While most roses will grow as well or better on a compatible rootstock, at least one rose, in my observation, is a little dwarfed by it.In the bed of ICEBERG at the Huntington Library, the own-root plants grow a little taller and fuller than the budded ones, possibly proving the exception to the rule.Or, perhaps the variety and its stock aren’t as compatible as they should be.Minature roses budded on a larger rootstock seem to grow a bit larger than they do as a rooted cutting.I have wondered if the reverse, budding a hybrid tea on a rooted cutting of a miniature, would act as a dwarfing mechanism, the process seed to grow dwarf fruit trees.Anyone interested in trying it and reporting their results?

I have experimented, as I’m sure just about everyone who buds roses has, with several shrubs and climbers as rootstocks.FESTIVAL PINK, my clear pink sport of FESTIVAL FANFARE, puts out long, thick, straight canes each season.They root well and have taken buds fairly well.I have admired the canes of CARDINAL HUME for several years.It has few prickles, roots like a weed and grows wonderfully long, straight, strong canes.This year, I placed four buds of BABY FAURAX on it as a three foot tree.All four have taken and are developing into quite a nice tree.Mike Tallman and Don Gers in Santa Rosa, California, have actually been successful in grafting the species, R. Persica  to the old Van Fleet climber, SILVER MOON.This is quite a fete as R. Persica is notorious for not being able to be reproduced by anything bud seed.

As you can see, many roses have been used my many people for rootstocks.Nearly fifty years ago,                Dr. Griffith Buck, who began his career at Iowa State University, was involved in a long-term experiment looking for an ideal rootstock which would withstand the rigors of a midwestern winter.Also, a stroll through the American Rose Annuals of the 1920’s to 1950’s will yield many articles on the research conducted by amateurs and professionals alike. This discussion is in no way intended to be comprehensive.

Once an eager amateur budder decides on the rootstock to use, the next issue concerns plant viruses. And that subject it better off left to those more educated and impassioned about the subject than I.

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