Rootstock for Apricot

I don’t think it would be a coincidence that exceeds the unlikeliness of you discovering a disease susceptibility that has been overlooked by the industry and the literature that serves it (I’m not certain this is the case- haven’t done that search).

I have made the majority of my mistakes in horticulture and probably life in general by exaggerating the importance (statistical significance) of my own limited anecdotal observation. Humans are hard-wired to do this.

I went yesterday to the Grafting workshop in Lancaster, Pa that was hosted by the BYFG. I picked up Plum rootstock (not sure what type) and Peach Krymsk rootstock. I might graft apricot on both and try them out.
There was peach borer problem in the past at my current property, but I’m going to plant them away from where peaches once were.
Now I wish I got some dormant plum scions to graft on the extra plum rootstocks I got.

I have done the search and here is the result:

S. M. Southwick and K. G. Weis, “Selecting and Propagating Rootstocks to Produce Apricots,” HortTechnology, vol. 8, no. 2, pp. 164-170 (1998). Table 1:

Good job. Thanks. I’m not sure how that relates to creating susceptibility in apricots. Now I’m curious about practical ramifications.

Actually, I don’t get much choice on rootstocks from my suppliers with apricots. They are always on myro or peach seedling and myro has not been a problem with the scores of trees I’ve ordered from ACN. in the last couple of decades, but this is in S. NY. Peach root has been a PIA because of borers…

Having just spent about 15 minutes searching for something related to commercial apricot production and relative merit of Myro rootstock, I’m guessing your reference may not have much practical significance as far as root stock selection.

Can you find any more specific research as it pertains to commercial fruit production- in other words, whether this susceptibility has any practical significance in choosing a rootstock for cots? I apologize if it seems like I’m just trying to protect my ego. This may be the case, but I think my motivation is wanting to keep this forum a very reliable source for useful information.

The most recent reference in the info you supplied does not recommend against the use of myro, and seems to favor it.

http://horttech.ashspublications.org/content/8/2/164.full.pdf

The borers will just as likely find them, I think. Just keep your eyes open for frass at the base of trees. Because I was used to Adam’s myro based rootstock I wasn’t in the habit of checking cots and borers got further into a couple of cots than they should have last year at 2 separate sites I manage.

Alan, I’ve just reported a tiny bit of evidence that I observed. Statistically speaking, the probability that two canker-susceptible varieties out of seven would both end up on the Myro rootstock is 1/21 (just under 5%). Possible? Yes. Likely? No. I obviously don’t have time and resources to conduct a scientifically meaningful experiment. And even if I did, my results would not necessarily apply to different climate and soil conditions. Just another piece of anecdotal evidence relevant to California: Fowler Nurseries (a big California wholesale nursery) currently does not offer apricots on Myro (see http://www.fowlernurseries.com/New%20Pages/Apricots.htm). They still use Myro for plums (see http://www.fowlernurseries.com/New%20Pages/Plums.htm), so there might be a reason why they exclude this rootstock for apricots.

No, your tiny sample and 5% odds mean almost nothing. If 20 folks on this forum grew a few apricots then the odds are one would experience some similar anomaly that would lead us to a false conclusion.

However, in CA, UC Davis doesn’t recommend myro, but not because of canker susceptibility. They suggest its graft unions are more likely to snap off in the wind. In the N.east I’ve had all kinds of problems with apricots- all related to cambium freeze but I’ve never had a tree snap at the union, so I doubt that is a big problem here. Selection of rootstocks is partially regional and ACN, the largest east coast supplier of apricot trees, propagates exclusively on myro.

http://fruitandnuteducation.ucdavis.edu/fruitnutproduction/Apricot/Apricot_scions__rootstock/

The above advisory is from Davis and apparently Citation is on the way to becoming the most popular rootstock for apricots in the state responsible for most of it’s commercial production in the country, so even if your issue is coincidental it may have steered you to the best rootstock for you. But the poster is an east coast grower so I’m not sure how this applies there.

He hasn’t suggested citation as an option. I like the rootstock but haven’t grown apricot on it.

I planted a Harcot and a Tomcot on Citation last year for trial. They both put on a lot of growth and looked great going into dormancy. This spring, the Tomcot failed to push leaves and the Harcot stalled just as the buds started to open. An investigation revealed that both were slowly dying back, but the trunks and some branches were still green with moisture. The Citation rootstocks, however, were completely dry and dead looking.

The rootstocks always survived in previous springtime apricot deaths . This is the first time I’ve seen death from the rootstock. I wonder if the polar vortex plunges are what killed them. Maybe it was high soil moisture prior to the polar vortex plunge. They were planted in two totally different areas of the property, but the soil doesn’t vary much.

Needless to say, I’m not very impressed with their hardiness in northeast zone 5 with silt loam soil that drains poorly. Considering they also have issues with stunting peaches and nectarines, I don’t think I will be using these rootstocks anymore unless it is for potted trees that will be sheltered from winter extremes.

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Alan,

Is your Tomcot on Myro?

Mine was on Citation. It looked great going into last winter, then died abruptly.

Same thing happened to my Moorpark on Citation. This rattled me pretty good, and I am gunshy about cots now.

Are you seeing the fair share of sudden death with Early Blush or OrangeRed? Do cots on Myro seem to die suddenly just as frequently as cots on Citation by you?

Would you think I am limited to Alfred and the Har series? Am I limited to Myro? Have you ever tried cots on Manchurian understock via Cummins? Okay, I’ll shut up now. 20 questions…

-Matt

I’ve been looking around some more.

I want to get a rugged tree, and graft multiple varieties onto it. I want to minimize the risk of sudden death/ cambium freeze from happening. My location can see warm winters followed by tricky late frosts. This past April, I think we both endured those terrible freeze events. They devastated my apricots.

I think I’m going to get a Hargrand tree on Manchurian to minimize cold damage.

Has anyone had any trouble with Mid-Atlantic summers being too hot and humid for Manchurian understock? Can the trees get too big? Or can simple pruning keep them a reasonable size without undue introduction of disease?

I have only one tree on Manchurian. Its done well. Definitely on the vigorous side, it was out of line until I started limb bending on it.

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My longest lived apricot (puget gold) is on k86… not sure if that is what is making the difference, but i’ve lost 2 Tomcot and a Hunza over the years. I might try apricot seedlings as rootstock. Having said all of this…that Puget Gold will probably now shrivel up and die.

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I get my Tomcots lately from Van Well, who, unfortunately, graft cots on peach seedling. This has led to issues with borers, especially because I don’t really have my eyes out for borers with cots.

What will work for you is not possible to tell, but Hargrand has tended to be the longest lived cot for me of all the varieties I grow. Orangered showed great signs in terms of maintaining high vigor on my property for 5 years but this seasons events seemed to have knocked it for a loop and I’ve had it die elsewhere at less than encouraging percentage. Early Blush has also turned out to be a bust at many “better” sites than mine but on my property is going strong after losing vigor and being cut back 2 years ago. It looks ready to bear a good crop next season.

The thing is that cots act weirdly at my site- usually not getting full cambium kill but instead maybe cam injury that dooms the trees to inadequate vigor to crop well. On other sites they tend to be live vigorously or die.

I haven’t used Alfred enough to evaluate it well. It does great growing against my east and south wall and even this season I got a few cots from it- the only ones I saw anywhere not in a grocery store. I put a Tomcot on the south side and it is looking very promising after 2 years of growth there.

I’ve never gotten cots on citation- they tend to be on Manchurian.

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I just added Hargrand on Manchurian for my spring Cummins order.

What about prunus americana? I have some apricot chip buds that i put on mine this year…we’ll see how they do.

I butchered my Buenos and let the K86 grow out…now i have to figure how to turn that into rootstock (cuttings?)…

My Puget Gold is from 2009…i have about 10 varieties on it…give or take.

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Could you dig up a decent size root and try to get that to grow? I butchered some roots on a crabapple trying to remove some stubborn kentucky bluegrass out of the mulch this spring and the roots I severed keep pushing new suckers.

I had to look K86 up, but this flyer makes Krymsk 86 seem like the best thing since sliced bread. http://p2g.us.com/wp-content/uploads/2014/12/krymsk-86-2014.pdf

I know…what’s the catch? Why isnt it used more often? I do hate that everything seems to come on Lovell or Citation (the stuff i order at least)… and i also battle borers nonstop so its one reason i’m looking into alternatives.

Not sure about digging it. It kept sprouting and then the new sprouts would get knocked over early this spring…it only finally took off in the summer and has put on a ton of growth. I’d rather try to root cuttings or something, but i’ve never done that either…so who knows.

My experiences with rootstock K86 for apricot are very good In addition, K86 propagation eassy by cuttings get fast roots!
Wavit rootstock is also recommended for apricot

K.86 looks to be a great stock for peaches. Massive adaptable well-anchored roots.

Jury is still out for whether it will enable apricots to survive the wild temp swings of certain locations here in the U.S.

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