Rootstock for Apricots, Peaches, and Plums
Peach seedlings (Prunus persica)
Maternal Parent: Bailey, Flordaguard, Guardian, Lovell, Nemaguard, or Siberian C
Commonly used for: peaches
Also used for: Asian plums, European plums, apricots
Limited compatibility: apricots are occasionally implied.
It seems that Lovell seedlings are used as a rootstock for peaches more often than anything else, but like the others from this species, they lack tolerance to wet and alkaline soil. Conversely, they perform fairly well in soils that are heavy or dry, but there are plum rootstocks, as well as some of there hybrids, that are more suited for such conditions. They are described further below. Lovell is semi-vigorous and quite hardy in comparison to most peaches, and as a rootstock, it is capable of handling temperatures down to zone 5a. However, there are seedlings from other varieties that perform better in the cold. In fact, a similar story seems to play out for Lovell in a number of cases. It does not excel over the others when it comes to resistance to pest or disease, but there is generally some distance between Lovell and the worst performers when multiple persica rootstocks are compared.
Bailey is a hardier and less vigorous alternative to Lovell, and it is believed to be similar or better in yield efficiency. Bailey is not mentioned as often as Siberian C for its exceptional tolerance of the cold, but the latter's popularity may not be justified. While Siberian C was tested to be hardier than Bailey in a lab, it seems to perform worse in real world conditions. Basically, a climate that is both cold and lacking in large temperature swings may be required for Siberian C to maintain a high survival rate, which would explain why nurseries in the north generally opt for Bailey or Lovell instead.
Certain types of nematode – such as root-knot, peach root-knot, and ring – can be quite detrimental to various stonefruit species, including the peach. This is particularly true when they are planted in soils that are sandy, but the likelihood of experiencing problems with them will also depend on the region. For example, the peach root-knot nematode is primarily found in Florida, and Flordaguard is the only persica rootstock that has demonstrated resistance to it. The more common root-knot nematode, however, has a very wide distribution, but it is more likely to be found in the west and the south than the rest of the country. Nemaguard is generally used against them, but it is not exactly a peach. It is a hybrid between Prunus persica and Prunus davidiana, the latter of which is very similar to a peach.
In the southeast, the ring nematode is relatively common, and it is responsible for making peach trees more likely to suffer from one or more problems associated with peach tree short life (PTSL). Rootstocks that have some resistance to the ring nematode, such as Guardian, should generally be used. Guardian also has some resistance to the root-knot nematode, but in this regard, it is slightly inferior to Nemaguard.
The greater peachtree borer is another pest of concern, but unlike the nematode, it is primarily an issue for persica rootstock. It will feed on the cambium of the first 6 inches or so of the trunk of many Prunus species, but they are particularly damaging to peaches. However, persica rootstocks are quite vigorous, especially if they are fertilized. This helps delay or prevent death from girdling, but protecting the trunk by painting it with kaolin clay or undiluted neem oil, or spraying it with some kind of insecticide, should be considered.
Some of the most serious diseases that persica rootstocks struggle with are armillaria (oak root or honey fungus), crown gall, verticillium wilt, and the prune brown-line disease, although the latter is rarely an issue, since prunes are generally not grafted to peaches. As for the others, I hear complaints about crown gall the most and verticillium the least, but none of them seem to be too common for home-growers. The same appears to be true when it comes to nematodes, but many of these home-growers, particularly those who live further to the south, tend to have clay soil, which is less suitable for the pest. Overall, Prunus persica clearly lacks resistance to pest and disease, but the studies I have seen strongly imply that when peach scionwood is grafted to a member of its own species, the trees tend to have a very high survival rate compared to many of the alternatives – when none of the problems mentioned here have a significant presence within the area.
In short, if you are restricted to using a persica rootstock for the peach or nectarine variety that you desire, which you generally are if you do not plan to graft yourself, then Bailey should be prioritized in the north, but Lovell is quite suitable as well. If you are in the south, then Guardian would be the safest option, especially if your soil is light or you suspect that your property is already plagued with the nematodes it resists, but if you are fortunate enough to find it, since it is quite rare at this time, the hybrid rootstock MP-29 would help protect the tree from a greater number of potential issues. However, Krymsk 86, St. Julian A, and the American plum appear to be the most common alternatives to persica rootstock for peaches, and if your soil drains poorly, at least two of them would be a more suitable option.
Krymsk 86 (Prunus persica x Prunus cerasifera)
Commonly used for: almonds
Occasionally used for: peaches, plums, and apricots
Limited compatibility: apricots
Krymsk 86 (zone 4b) is a semi-vigorous rootstock that performs well in a wide range of soils, but its most unique trait is that its anchorage is exceptionally good. This greatly helps the tree stand upright in areas that frequently experience winds strong enough to cause other grafted trees with high vigor from this genus to occasionally lean or fall over. Krymsk 86 also has some resistance to armillaria and verticillium wilt, and it is relatively tolerant of alkaline soil. Additionally, it performs better than persica rootstock in dry conditions, but they, too, are quite tolerant of it. However, K86 lacks any significant form of resistance against nematodes, although it may not be the most susceptible to lesion, and it is probably susceptible to crown gall as well.
Myrobalan 29C (Prunus cerasifera)
Commonly used for: plums, apricots
Also used for: peaches
Limited compatibility: apricots, peaches
Myrobalan 29C is a semi-vigorous clonal alternative to myrobalan seedlings that you can use if you wish to have a better idea of what to expect from your rootstock, but this species, in general, is quite tolerant of heavy and wet soil. Myrobalan 29C is resistant to the root-knot nematode, which seems to include the Florida variant, and it supposedly has some resistance to verticillium wilt and crown gall as well (the latter of which is uncommon with this species). Conversely, it is susceptible to bacterial canker and prune brown-line disease, and it has a tendency to sucker, although not as often as Marianna 2624 or most myrobalan seedlings. Additionally, the roots of 29C can be quite shallow for a few years, which makes it vulnerable to high winds. Descriptions about its tolerance to armillaria are fairly contradicting, but it is likely susceptible.
St. Julian A (Prunus domestica)
Commonly used for: plums, peaches
Also used for: apricots
Limited compatibility: apricots, peaches
St. Julian A (zone 4a) is a semi-vigorous rootstock for plums, but for the peach and apricot varieties that are compatible, it is semi-dwarfing. While Julian is said to tolerate a wide range of soils, it may not be as versatile as some of the other rootstocks. In fact, the extent of this is not entirely known, since there is some uncertainty about its use in the eastern half of the United States. Whether its "inferior survival rate" is related to the cold, wild temperature fluctuations, moderately-high rainfall, soil-type, or some combination of these, I am not sure, but it seems to perform better than Citation within this region, which is another rootstock that is commonly used. I do not recall seeing anything about nematodes concerning this rootstock, but it should be at least somewhat resistant to crown gall.
Marianna 2624 (Prunus cerasifera x Prunus munsoniana)
Commonly used for: plums
Also used for: apricots, almonds
Limited compatibility: apricots, almonds
Marianna 2624 is somewhere between a semi-dwarf and a semi-vigorous rootstock that is tolerant of heavy and wet soil, but it, too, has roots that are quite shallow during the first few years of growth. Marianna is resistant to the root-knot nematode and prune brown-line disease, but it is more susceptible to bacterial canker than most, if not all, of the alternatives. This can, however, be countered by grafting close to the ground. It is also susceptible to crown gall and the almond brown-line disease, and it tends to sucker profusely. 2624 is less tolerant of armillaria than Krymsk 86. In fact, a few studies indicate that it may not be as tolerant of the disease as some descriptions imply.
American Plum (Prunus americana)
Commonly used for: American x Asian plum hybrids
Also used for: peaches, Asian plums
Limited compatibility: peaches
(European plums may commonly experience delayed incompatibility)
American plum seedlings can be used as a cold hardy, semi-dwarfing rootstock for some peach varieties, such as Redhaven, Contender, and Saturn, but they are more commonly used for American x Asian hybrid plums. One of their more positive traits is that they can tolerate a wide range of soils, but there is some contradicting information about their ability to handle drought. The information that I have seen, however, (as well as some experience of my own) leans towards the implication that it is quite tolerant. I haven't seen any substantial information about its performance against armillaria, verticillium, or nematodes yet, but it "might" be susceptible to crown gall and it might have some resistance to verticillium wilt, since plums are known for being less susceptible to this disease than the other stonefruit. The uncertainty comes from the high number of plum species that exist, and I am sure there is plenty of variation in resistance between those we aren't too familiar with.
MP-29 (Prunus umbellata? x Prunus persica)
Occasionally used for: peaches and Asian plums (as well as their hybrids)
MP-29 is a semi-dwarfing rootstock that should have a good amount of tolerance for heavy soil and, perhaps, some tolerance for wet soil (based on its parentage), but unlike the others that fare well in such conditions, MP-29 is quite resistant to armillaria and peach tree short life (PTSL), both of which can quickly lead to the death of the tree. It has also demonstrated resistance to the root-knot and the peach root-knot nematode, but it may start to produce suckers some distance away from the tree after five to seven years of growth. Overall, this rootstock has an exceptional amount of positive traits that those in the south may find especially desirable, since some of the afflictions that it performs well against are relatively common there. Unfortunately, MP-29 is a fairly new rootstock, and at this time, it is not widely available.
Citation (Prunus salicina x Prunus persica)
Commonly used for: apricots, plums
Also used for: peaches
Limited compatibility: peaches
Citation is a fairly precocious and dwarfing or semi-dwarfing rootstock, but it is not ideal for dry or heavy soil. It is said to tolerate excess moisture quite well, but there have been numerous complaints about this rootstock dying in soils that were saturated in late winter or early spring. However, I believe all of these complaints came from people in the eastern half of the United States. A low survival rate has also been observed in a few trials that involved Citation within this region, and considering that one of the papers I have seen claimed that Citation lacks cold hardiness, in some form, it is possible that the climate had something to do with this. A few other potential issues with this rootstock is that it is susceptible to armillaria, crown gall, and bacterial canker, but it has some resistance against the root-knot nematode.
Krymsk 1 (Prunus tomentosa x Prunus cerasifera)
Commonly used for: plums
Also used for: peaches, apricots
Limited compatibility: peaches, apricots
Krymsk 1 is another relatively dwarfing and precocious rootstock for various kinds of stonefruit, but with the exception of plums, it seems to have more compatibility issues than Citation. It tolerates heavy, wet, and slightly alkaline soil, and it has some resistance to the lesion nematode. There is some contradicting information about its performance against the root-knot nematode, but it should, at the very least, be less susceptible to it than most persica rootstock. It is also less susceptible to armillaria, but in either case, you should not rely on this rootstock in areas known to possess these afflictions. Furthermore, it lacks resistance to bacterial canker, crown gall, verticillium wilt, and it does not perform very well in soils that are left to dry. Overall, it has quite a few similarities to Citation, but Krymsk 1 should be a more suitable option in the north and, perhaps, the more central part of the eastern half of the United States. As you go further south, its survival rate declines quite dramatically, based on trials performed throughout the region.
Nanking cherry (Prunus tomentosa)
Occasionally used for: European plums, Asian plums
Possible (to some degree): peaches
There does not seem to be much information out there about the Nanking cherry, but what is apparent is that it induces low vigor and is fairly tolerant of alkaline soil. It is also hardy enough to handle zone 2 temperatures, and its ability to resist the ring nematode appears to be exceptional. The Nanking cherry is likely susceptible to armillaria though, and it may be susceptible to bacterial canker. Either it is less so than some of the alternative rootstocks, or it varies considerably by seedling.
Sand cherry (Prunus besseyi or Prunus pumila)
Occasionally used for: American x Asian plums
Possible (to some degree): apricots, peaches, European plums
Limited compatibility (known): apricots, peaches
The sand cherry (zone 3), when used as a rootstock, produces something between a dwarf and a semi-dwarf tree, but non-hybridized forms, such as Pumiselect, are not commonly used. Pumiselect is fairly compatible with peaches and apricots as well as various kinds of plums, the latter of which it is most closely related to, but in North America, you are likely restricted to seedlings, since Pumiselect is quite rare. This may lead to problems, since one article claimed that sand cherry seedlings were once used for peaches, but are no longer, because it was common for some varieties to suffer from delayed incompatibility after 5 years or so when grafted to this species.
The sand cherry can tolerate a wide range of soils, but it may struggle in those that are excessively wet. Additionally, it seems to be resistant to quite a few problems that occasionally plague other stonefruit rootstock, such as crown gall, bacterial canker, and the root-knot nematode, and it seems to have some level of resistance against the lesion and the ring nematode as well. However, I am not sure how it fares against armillaria and verticillium wilt at this time, and unlike some of the other dwarfing rootstocks for stonefruit, those grafted to a sand cherry may need to be staked.
Related: Apricot, Peach, and Plum Varieties