Please help me choose apricot rootstock

I am looking to buy a new Harglow apricot. So far I found 2 choices: I can buy it from Raintree on St Julian A rootstock or from Bay Laurel on Citation.
Here is information about planting site.
Soil: good garden soil, former garden bed.
Location: Worcester, MA, zone 5B
Drainage: good
Pests: root knot nematode
Climate challenges: Fluctuating spring weather, sudden rise or drop of the temperature with 30F delta possible in 2 days. Inconsistent snow coverage in winter.
Desired tree size: small with pruning

When I read about the two rootstocks, it feels like I need both of them for one tree. :grinning:

Citation
interspecific peach & plum-rooted cutting highly compatible with apricot and plum,
induces early bearing, tolerant of wet soil conditions, resists root knot nematode,
advances maturity and increases size and sugar content of fruit
susceptible to crown gall, bacterial canker and oak root fungus, intolerant of virus with peach or
nectarine

St Julian
Semi-dwarf rootstock for cold areas with fluctuating spring temperatures due to inconsistent
spring weather conditions. Preferred over Citation in north coastal mountains and Oregon.

How bad are root knot nematodes for St. Julian? This is one of the issues I can’t correct, I had to move my carrots to containers to get the crop, otherwise it didn’t survive even seedling stage, but other cultures are not bothered much by them - I can see the knots on some . roots like beets or turnips, but they do not stop development.
Also for St Julian there is no any disadvantages listed. How is it with bacterial canker? This is the second issue I usually have with stone fruit.

I can tell you are really wrestling with your decision, so I just wanted to suggest contacting this gentleman:

Mr. Purvis has forgotten more than a lot of people know about apricots. He might be able to recommend a good rootstock/apricot combo for your area. I contacted him about a good apricot for success in the South. He was very patient and knowledgeable and had no problem answering my questions while I picked his brain.

(I did end up purchasing something from him and will probably continue to patronize him when he has something I want, but he was just truly happy to share his knowledge, like many of the experts on here. This is a wonderful hobby where we can learn from the “giants” in the field, and most of them truly believe in passing on their knowledge to the next generation.)

Good luck with your decision.

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Thanks, I will!.

I received the response from Robert and desided to go with St Julian A

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That’s funny, I would have gone with citation. What was his reasoning? Has he discovered the trees to be hardier on more dwarfing rootstock. Survival is the key issue for apricots in the northeast and Bob doesn’t have experience growing cots here.

I have no experience growing them on citation or St. Julian, but I am under the impression SJ is more dwarfing and my inclination is to want a more vigorous tree, thinking it might be hardier. My trees are always on myro or peach and I prefer myro so I don’t have to worry about borers.

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Myro and peach produces full size tree, correct? I have to have it dwarf, or at least semi-dwarf.
Here is his response:
I’ve had Prunus growing on St. Julian A and on Citation here and also had a few pluots on Citation in Minnesota. What I can tell you about Citation is that it is widely used as a dwarfing rootstock in California, and it seems to be compatible with all apricots. Citation seems to tolerate heavier soils, but it does not tolerate drought real well. It is also less cold hardy than St. Julian A and will produce an apricot tree about 50-60% as large as the same cultivar budded to peach. Given your USDA Zone and inconsistent snow cover, I would be a bit hesitant to plant Harglow on Citation.

St. Julian A would give you a more vigorous tree, which is not a bad thing because Harglow has a compact growth habit. St. Julian A would be a better choice from a cold hardiness and drought tolerance standpoint. According to Rom and Carlson’s reference, Rootstocks for Fruit Crops, St. Julian A is susceptible to bacterial canker, but if very little of the rootstock is above ground that should not be an issue. I cannot find any information about tolerance of either rootstock to root-knot nematode but feel safe in saying that the more vigorous the rootstock (St. Julian A versus Citation), the more it can tolerate some degree of infestation from nematodes. An apricot tree grown on St. Julian A will be about 70% as large as one on peach or Manchurian apricot rootstock, as I have seen here.

Bottom line: if I were in your situation, having observed and read about rootstocks as I had, I would go with St. Julian A as the rootstock of choice. The only drawback I have seen here (and this is never an issue in the deep, rich, well-drained prairie soils of Southwest Minnesota for my buddy John Fuerst’s plum trees on St. Julian A) is a tendency to sucker from the roots if the soils are shallow or poorly drained.

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Looking into it I see my memory was mistaken about St. Julian being less vigorous than Citation. Apparently it is almost as vigorous as myro and described as having 80% vigor of a “standard”. I’m not sure it is better for your purposes than myro as 20%, if that’s correct, isn’t much difference- how the tree is trained would be a much larger factor.

With the info I have now, I would probably try St Julian also, except that I’ve already had very good results with plums on Citation that I’ve managed for 15 years in wet, heavy soil. The comfort of past experience always holds some sway.

Thank you for expanding my knowledge of these root stocks.

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I’m naive about this subject but what is wrong with Manchurian apricot seedlings for rootstock. They show no disease and are not overly tall (15’).

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The problem I’m aware of is that nurseries don’t often offer them as rootstock.

I planted Manchurian apricot trees at a site and they were actually quite fragile in our conditions- at least at that site and quickly died out. Sometimes trees from very cold places don’t take fluctuating winter temps well. Of course, that doesn’t mean they couldn’t work as rootstock.

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Ok, I started with St Julian and Citation because I could find these two for the apricot I like. But while I am doing my research, I started to think I may be better graft scion of apricot I have and like to rootstock I can buy. Then I guess my choices of rootstock could add Krymsk 1 from Raintree. What is good and bad about it? To keep tree small is a must for me, very limited space.

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Below is some info I collected about Krymsk 1 from various sources. @fruitnut reported incompatibility issues with some apricots. I think he has most experience with growing apricots on K1. This spring I grafted five apricot varieties on one K1 rootstock and 4 out of 5 took. They seem to be growing ok. I mostly used K1 for E. plums and A. plums and so far it seem to be a very good fit. With peaches/nects on K1 I had about 50% success rate, so Redhaven interstem would be advisable.

Maas et al.: Krymsk 1 (Prunus tomentosa × Prunus cerasifera) was selected by Gennady Eremin at the Krymsk Breeding Station in Russia in 1966. In comparison to St. Julien A on many European Plum cultivars, trees on Krymsk 1 were by far the least vigorous, most precocious, and most production efficient.

Bay Laurel: Dwarfing rootstock for peaches, plums, apricots and nectarines. Produces a tree about half the size of standard, roughly eight to fourteen feet. Does very well in heavy soils.

gb-online.co.uk: A semi dwarfing that grows to approx 2-2.5 m tall, comes into fruiting very early with high production. More suited for heavy soils and winter hardy.

anfic.com.au: Cold tolerant, drought tolerant, waterlogging tolerant. Looks very good in the trials for peach, plum, nectarine, and apricots. Dwarfing at least 50%. Fruit size is very good - better than Lovell on young trees. Some incompatibilities are reported in Spain with low chill nectarines. We have never seen any incompatibilities. Adaptable to many soil types including heavy soil. It does not resist stress well and can have a problem with transplant shock if not handled well. Requires good irrigation practices or the trees will be very dwarf. Seems susceptible to Pseudomonas. Good yield efficiency. Reports from California: Very good enhancement of fruit size; apricots have a good balance of renewal growth; larger fruit of Japanese plums compared to Citation. Reports from Holland: 60% of full tree size for plums; increased fruit size; less dwarf with plum than peach; could be the best apricot rootstock, check compatibility but it occurs early; susceptible to bacterial canker (although never seen in the field); some resistance to nematodes.

2002 NC-140 Peach Rootstock Trial at Geneva: Krymsk 1 (along with Controller 5) showed the greatest survival rate and the greatest percentage of functional canopy.

UC Fruit Report: In NC-140 trials with Redhaven, Krymsk 1 has been very impressive - healthy looking dwarf trees with little suckering, good production and large fruit size. Compatability with Redhaven has always been good. However, many other California varieties have been grafted on Krymsk 1 and many of these show signs of poor compatability. A report from Spain also indicated compatability problems with some varieties. Anchorage: Good, Rootknot Nematode Susceptible; Lesion Nematode: Resistant or tolerant; Ring Nematode: Susceptible; Bacterial Canker: Susceptible, Crown Gall: Susceptible.

Gerard Poldervaart: Krymsk 1 (VVA-1, P. tomentosa x P. ceracifera) is compatible with dessert and culinary plums, apricots, peaches and nectarines. In Europe, it is mainly used for plums. Trees grow very weakly on VVA-1 and their productivity is very high. The fruit size on VVA-1 is typically better than on St-Julien A or similar rootstocks. However, trees on VVA-1 can easily carry too many fruit, and therefore thinning is needed to achieve good fruit size. In dry conditions, trees on VVA-1 often grow too weakly. In most cases, an effective water supply is an absolute necessity for trees on VVA-1. Trials in Europe show that VVA-1 is very compatible with almost all varieties of dessert and culinary plums.

Fruitnut: Graft incompatibility of Montrose apricot on Krymsk 1 (reported July 2016).

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My mountain orchard is zone 6b, with nasty fluctuating springs like Massachusetts.

I have had 3 separate robust apricot trees on Citation DIE. One of them was a Tomcot. Another was a Moniqui.

Apricots do not like temperature fluctuations. Late spring frosts KEEL them. Citation does not have what it takes to get them thru these difficulties.

I also had Hesse plumcot on Myro die for unknown reasons.

Planting them on the north side of a building/ wall/ barrier/ downslope might help them wake up later in spring.

I planted Hargrande on Manchrian this past spring. We’ll see how it does. I grafted Zard onto it as well. Zard is supposed to be the latest-blooming cot.

Fedco sells cots on Manchurian. Cummins too on rare occassion. St. Lawrence sells a selection of Manchurian with supposedly palatable fruits.

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@Stan, thanks a lot! Some of that info in found in Google and on this forum, but most I never saw, thanks a lot!

@Matt_in_Maryland, so Citation is out of question I guess. Thanks fo sharing!

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