Propagating Roses

Grafted vs. Own-Root Roses

By Malcolm M. Manners

I've had several conversations with local society members, lately, about the relative advantages and disadvantages of grafted and own-root roses. Much of what has appeared in print was written by authors in other climates and with different soil conditions than those of Central Florida. So I thought the subject might be worth an article. First some concepts:

The term "own-root" refers to roses that have been rooted from cuttings, divided, layered, tissue-cultured, or produced by some other method which caused a branch to produce roots of its own.

In contrast, a grafted or budded plant is one in which a small piece of the desired flowering variety (the scion) was surgically attached to a root system from another rose (the rootstock, understock, or just "stock"). These two parts heal together, to become a single plant.

Budding is a type of grafting, and the terms are often used interchangeably. While methods of nursery production differ slightly, budded and grafted plants should behave identically in the garden, and any reference to "grafted" plants in this article is meant to include budded plants, as well.

Own-root plants have some significant advantages over grafted plants. Own-root plants are usually cheaper, since they take less time to produce, as well as less skilled labor and often less total labor. Own-root plants also tend to live longer than grafted plants in a soil to which they are well adapted. Also, if an own-root plant freezes to the ground, it will usually sprout back out from below the soil surface. The sprouts are still the original variety, so you haven't lost the plant. So, in many areas of the country, you may find own-root bushes 50 or more years old, sometimes much more. However, if a grafted plant freezes to the graft union, the rootstock may sprout out, but you will have lost the original grafted variety. The biggest disadvantage of an own-root rose in Central Florida where I live is that relatively few rose varieties are well adapted to our soil conditions. We have light, excessively well-drained, high-temperature soils, not at all ideal for most roses. While we can certainly improve the situation with the addition of generous amounts of organic matter, a problem we can't eliminate is nematodes -- tiny worms in the soil. Most Florida soils are infested with many species of nematodes, some of which are entirely harmless, while others feed on plant roots. The most serious group on roses is the root knot nematodes (Meloidogyne spp.) If a rose is not resistant to these pests, it will not likely be successful on its own roots, here. Roses are not either absolutely resistant or susceptible; rather, there is wide variation from one rose cultivar to another, in the level of resistance. Often, an own-root plant will grow rapidly and healthily here, at first, then become less vigorous after a year or two, eventually becoming so unhealthy that it needs to be replaced. Others decline shortly after planting, while still others are highly resistant and may survive and thrive for many years.

The mere fact that a rose is grafted or budded does not insure that it is better adapted to a certain soil condition or more resistant to nematodes than an own-root rose would be. It is important to select a rootstock that is specifically adapted to your situation. It is by selecting a rootstock to match the local soil, that one can obtain a plant that is superior to an own-root bush of the same variety. While many rootstocks have been tried, there are only five in common use, in the United States.

Multiflora is a popular rootstock in Texas, Canada, and parts of the northeastern U.S. It is not at all well adapted to Florida conditions, in that it apparently needs more winter chilling than we normally get, and is highly susceptible to root knot nematode. Multiflora-rooted plants in Central Florida seldom thrive, even when first planted, and nearly always die by the third or fourth year. Florida growers would do well to avoid this stock. If you can't find a particular variety on any other root system, at least plan to transfer a scion to another stock as soon as possible, from your multiflora-rooted plant.

Manettii is another stock sometimes encountered. Wayside Gardens sells plants on it; I'm not sure why. While not a terrible stock, it has little about it that is worth recommending, for our climate or anyone else's. Manettii is probably best used as an understock for greenhouse-grown roses.

By far the most commonly used stock in the United States, almost always produced in California, is Dr. Huey ( Shafter ). A plant on "Huey" roots tends to be a strong, healthy grower in Central Florida, for the first 5 - 6 years. During that time, it grows and performs nearly as well as any other root system that we can use. However, after several years, the nematode population builds up to high enough levels that the plant can't replace roots as rapidly as they are being destroyed, and the plant declines. This process can be slowed down by using large quantities of organic matter in the planting hole and by keeping the bush deeply mulched, but ultimately, the plant will succumb to the nematode attack. It is rare to find a Huey rooted bush 10 years old, or a really healthy one over 5 years old, in Central Florida. So, Dr. Huey is an acceptable, even good, stock if you don't mind replacing your plants every few years. But if you want a long-lived plant, Dr. Huey is not the best choice.

Fun Jwan Lo a.k.a. Odorata or Indica Major , is a semitropical rootstock, which is badly cold-damaged even here in Lakeland. In coastal South Florida, it has some strong proponents, since it seems to be rather forgiving of calcareous (high pH lime rock) soils, but I can't recommend it in areas that freeze. Also, in most areas of Florida, Fun Jwan Lo tends to produce a less vigorous bush, with fewer flowers, than either Dr. Huey or Fortuniana At least in our garden, it also produces far more suckers (sprouts from below the graft, which have to be removed) than does any other stock we've tried. Its nematode tolerance appears to be similar to that of Dr. Huey . Fun Jwan Lo has the advantage of being unusually easy to root from cuttings, and to graft with a high degree of success.

Fortuniana, also sometimes known as "Double Cherokee," is currently the most popular rootstock in Florida. Note that it is not the same as the Cherokee rose ( R. laevigata ), although the Cherokee rose is believed to have been one of the parents of Fortuniana . Fortuniana is semitropical and can be badly injured in a freeze, but it has been our experience that it is substantially more hardy than Fun Jwan Lo . In the Christmas, 1989 freeze, we lost nearly all of our plants on Fun Jwan Lo but didn't lose any plants on Fortuniana or Dr. Huey roots. Fortuniana is also the most nematode resistant of all our rootstocks, allowing it to grow vigorously for 30 or more years. No one knows exactly how long such bushes may thrive, because the earliest grafted plants on Fortuniana in the State are less than 40 years old, and some of them are still quite healthy. Plants on Fortuniana are sometimes slower growing during the first few months after planting, than plants on some other stocks, but once established, they quickly catch up with, and surpass the growth of plants on any other root system. Fortuniana makes a very far-reaching root system, extending out many feet from the bush. It is more drought-tolerant than any of our other common stocks, and it is able to extract fertilizer nutrients from a wide variety of soils. Plants on Fortuniana ultimately grow to be unusually large. So, if you see an estimated height and/or width printed for a variety, you should assume that it will get substantially bigger if grafted on Fortuniana roots. With any grafted plant, it is important to watch for suckers -- stems growing out from the rootstock portion of the plant, below the graft. If allowed to grow, they will eventually crowd out the scion, and the graft will be lost. Many grafted plants are short-lived because no one bothers to desucker them.

A convenient aspect of Fortuniana is that its leaves are drastically different from those of most other roses, so suckers are easily recognized in the garden, even when quite small.

Considering all of the above information, which type of rose plant is best for a Central Florida garden? There are some roses which are excellent on their own roots. Some of the Chinas, for example, have been known to live 70 or more years, here in Lakeland, on their own roots. Old Blush, Louis Philippe and Archduke Charles are among this group of roses. Some Teas and Noisettes may also be grown for a number of years on their own roots, but I would caution you that, in nearly ten years of searching, I have never found an own-root Noisette over 5 years old in the Lakeland area, nor have I found a Tea more than about that age, unless it was growing next to a concrete building or slab. On three occasions, I've seen very old plants of Mrs. B. R. Cant (a Tea) growing next to a building. We have a plant on our campus that is at least 40 years old growing right next to a concrete sidewalk. Note that nematodes don't do well under heavy mulches, and in this case, concrete is a "heavy" mulch! We've never found any other own-root Tea in this area, regardless of its proximity to concrete. In addition to the roses mentioned above ( Louis Philippe, Archduke Charles, Old Blush and Mrs. B. R. Cant ), here is a list of all of the other roses I've ever found in Central Florida, growing healthily on their own roots:

Of course, big old plants of Fortuniana are common, probably nearly always the remains of a formerly grafted plant. I wouldn't hesitate to recommend any of these roses on their own roots, for this area of the State. But I would not recommend any other own-root roses for Central Florida, unless you know that the variety has been grown successfully, for many years, or unless you are willing to replace the plant fairly soon. If you want to gamble, other Chinas seem most likely to be successful, followed by some of the Teas. Somewhat north of here, where the clay content of the soil is greater, the situation changes. Many roses do well there, on their own roots. This is probably because root knot nematodes do not thrive on heavy, clay soils. But that is not the case on our sandy, non-clay-based soils.

I think it is a very important observation that you just don't see old own-root bushes of other varieties in this part of the State. There must be a reason for that, and I think it is that the plants have all died, due to their inability to adapt to our soil and pest conditions. Many people are planting Tea roses on their own roots, in this area, now. I wish them luck and success, but until those plants become several years old and are seen to be still thriving, I won't recommend own-root Teas for this area. I would always elect to put them on Fortuniana roots, as I would all other roses not listed above. One might ask if there are any disadvantages to a Fortuniana rooted bush in this area. I can think of only two: It may be somewhat more cold-tender than an own-root plant, and it will require some sucker removal during the first few years. I don't consider either of these to be extreme disadvantages, and I think the advantages far outweigh them, in most cases.

NOTE: If you are aware of an own-root rose in Central Florida, not listed above, that you know to be more than 10 years old, please tell me (Malcolm M. Manners) about it. I'm very interested in such roses.