Another Plum Mystery

It’s kind of a nice mystery but a mystery never the less. This photo is of the plums on my Mariana plum tree. Yes, this is Mariana, normally grown as root stock. I bet there is a many a grafted plum tree out there that isn’t as good as the root stock, in the case of Mariana, if only the root stock was given a chance.

Actually Mariana’s reputation is that as a fruiting tree it bares sparsely with very small but delicious plum. I’m guessing the people who wrote that description has never tried pollinizing Mariana with hog plum, Prunus umbelata? The three times before when Mariana bore fruit, it was apparently pollinized by Green Gage. The crops were always sparse, and the plums were always really small. Last year after Green Gage died, all three of my three adult plum trees bloomed together, but Mariana only made about five very puny plums. I did some research and discovered that our local native P. umbelatta which bloom with Mariana is a super close relative to the Munson parent of Mariana. So I brought a bucket full of P. umbalata flowers in the yard, this is the crop I got rewarded for my efforts with.

It seems clear to me that P. umbelatta as a pollinizer is the reason for the abundance of plums. But here is the mystery. Why are the plums so large? A possible explanation is that I gave the tree some Epson salts to take care of a possible magnesium deficiency in the soil. But I gave all the plum trees Epson salts, and the Toole’s Heirloom plums are unusually small this year. These plums are huge in comparison to what this tree has ever produced before, and it has a least six times the amount of fruit lode on it.

Can a fully compatible pollinizer result in higher quality plums? My intuitive thought is that it would result in more plums, not bigger plums. If having a better pollinizer does result in bigger plums, what’s the mechanism. The fruit has the genetics of the mother tree, not the pollen parent. Besides hog plums are tiny bitter plums. Could it be that the hog plum genes are stimulating the seed embryos to secrete hormones that are causing the ovaries (plums) to grow bigger? The individual plums are at least twice the size of the ones it produced in 2016 and 2015, Mariana is by far my favorite of my plums for fresh eating flavor. I can’t hardly wait to try these beauties. By the way, this a 20 foot tall, 30 foot diameter tree with the whole tree loaded like this. If Mariana can be made to produce like this, why is it just relegated to root stock? God bless.


I have never heard of a pollenizer increasing fruit size. Very interesting! The Epson salt could have done it, if the tree had a deficiency. Just because the other trees didn’t respond the same way doesn’t rule it out. The other trees could be lacking an additional nutrient, water, ect… that prevented them from reaching the same fruit size.

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Mariana is such a good girl! Whoever says Mariana is just root stock hasn’t given her a chance. She is the Cinderella of the plum world.


Looks like a good crop of plums. Do you prefer to eat them mostly fresh or make jelly/preserves with the Mariana? Just curious if I were to plant a Mariana Plum, I’m seeing a couple different varieties, ‘2624’ and ‘M40’ specifically, which should I get or will there be any substantial difference in fruit between the two?

I found some info in the patent information comparing Mariana ‘M40’ and ‘2624’:
“The stone is approximately one-half the size as that of the Marianna 2624 cultivar.”
"The date of bloom was substantially the same as that of the Marianna 2624 cultivar. "
“Superior rooting anchorage when compared to the Marianna 2624 cultivar.”
“A substantially lesser propensity to form suckers than the Marianna 2624 cultivar.”
"Also, the new cultivar when compared per se to the Marianna 2624 cultivar is found to set considerably more fruit, to form smaller fruit, and to possess a pit that is considerably smaller. "
Does this M40 picture fairly accurately resemble your Marianna? IMG_0684
Would love to know your opinion on ‘2624’ or ‘M40’ as a Marianna Plum for fruiting purposes.

The leaves look similar as best as I can tell from such a small photo. What would be most useful would be if the article contains the specific measurement range for the stones of both varieties. Back when I was researching Mariana and found some of these old articles about the various strains, I did not have fruit or seed. I plan to do some plum processing for jam tonight and in the process will take measurments of a random sample of fruit and seed. Maybe the article you have contains enough information to get us to lean towards one over the other or make us conclude that it’s another strain. The stones seem pretty uniform in size. The fruits are much more varied and are much bigger this year than in previous years. The specific measurements would be helpful for comparison sake since this tree could be yet another strain.

Really what I aught to do is now that I have lots of photos is send them to Trees of Antiquity with the simple question, “What is this?” “It came from you, and I’m pretty sure it’s Mariana root stock, but I’m not sure and it’s so good that I’m beginning to wonder if it’s really a European plum or a Euro seedling that got confused with root stock.” Whatever it is it’s a very good plum with European qualities for a climate where European plums don’t usually work at all. They were the ones that told me it was Mariana, but that was based off of a picture I sent them of the very first plum which did not at all match the description of the Jefferson Plum.

Here is a possibility. Trees of Antiquity just might be using Mariana seedlings for root stock instead of rooting Mariana. If so, this might be a hybrid with one of the European plums in their stock. God bless.


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Here are a few measurements for M40
Picking.–The fruit ripened from Jun. 7 to 14, 1996.

Size.–Small and relatively uniform. Average axial diameter is approximately 26 to 32 mm., the average suture diameter is approximately 26 to 32 mm., and the average cheek diameter is approximately 26 to 34 mm. The fruit is of such small size that it has no significant commercial value as a fresh fruit.

Form.–Variable in form, globose to oval in lateral aspect, and in the apical aspect varies from globose to slightly oval. The fruit commonly is quite symmetrical.

Stone type.–Full clingstone with numerous fibers connected to the flesh over the entire surface of the stone.

Stone size.–Small and commonly ranges from approximately 15 to 18 mm. in length, approximately 11 to 13 mm. in width, and approximately 7 to 8 mm. in thickness. The stone is approximately one-half the size as that of the Marianna 2624 cultivar.

Stone form.–Somewhat variable, most frequently oval, and at times approaching ovate.

Please let us know how Trees of Antiquity responds if you ask them.

Fruit size more or less matches for Marinana 40 but with these being a smidgen bigger. Of the ones I sampled the range was 29 mm to 34 mm with the average coming to 32.7. However stone size was much bigger, close to 20 mm long. My guess is that this is eather 2624 or a different strain. If I remember correctly, 2624 is the F1 hybrid between P. cericefera and P. munsonia and is the one notorious for not being productive. There is research out of U of Saskatuan which indicates that hybrids between Asian plums and American plums or Canada Plums are only fertile to the pollen of the wild type American species. In conversations with Rick Sowouskie one of the technicians there, he indicated that he believed that wild Chickasaw pollen would be much more effective at pollinizing an Asian hybrid with any of these three North American species than a hybrid between any of them. He thinks its a physical issue. Asian pistols are shorter than those of P. americana, P. canadensis and P. angustifolia. The hybrids also have a long pistol. He believes that the Asian genes prevents the hybrid pollen tube from growing long enough to make it to the ovum of a hybrid plum flower. Anyway, something similar may be going on with Mariana 2624, but I can say this. I have not measured the length of the pistol of any plum species, but Mariana plum flowers are over twice the size of wild hog plum flowers. Anyway, if the hog plum is a lot more effective at pollinizing Mariana 2624 than a P. domestica or a P. caricefera, it’s probably because it makes a more vigorous pollen tube for some reason. And the problem with the others may be that the Mariana flower is too big. God bless.


I sent them an email but their system does not allow for photos. We shall see how they respond. God bless.


The rest of the description of the fruit of M 40 in the patent does not appear to match your photos well. The patent describes the skin as “highly acid;” is that your experience?

If anything the skin is tasteless. This plum fits the description of a good European plum in every way except size, cling stone and the fact that it’s apparently more cross fertile with P. umbelatta than P. domestica.

I made spiced plum jam using a Marcus variation of the recipe found in the Ball canning guide. The main substitution was muscadine juice in place of apple juice.

Between the muscadin, cardamom, and the unique almost cherry like characteristics of the Mariana plum, the plum jam almost tasted like it was made with cherries instead of plums. Anyway, here are the photos.


So far I have taking over 19 gallons of plums off of Mariana. There is over a gallon to go. I’ve weighed a representative sample of the gallon bags full of plums, and they are just under 4 pounds per gallon. When all is said and done, Mariana has produced about 80 pounds of fruit which I think is about what one would expect from a commercial plum variety under commercial orchard conditions. The plums picked while colored up but still firm are holding up just fine under normal refrigeration, way better than Robusto would. As long as their is hog plum around, this is an excellent plum option for the Deep South.

LOL! I took a bag of plums to the local nursery in town and told the new manager, you guys need to carry this plum variety. He asked, “What is it?” I told him just try it and then I will tell you. He bit into it, and his face lit up and he said: “Damb!” What is this? I told him it was Mariana plum root stock. He said, “What?” Then I explained how I got it and how its not supposed to be productive at all and them about it suddenly producing a massive crop after I brought hog pollen in the yard. About that time an employee walked in and the manager handed him a plum. The employee asked, “What is this?” The manager said, never mind, just take a bight and tell me what you think. The employee took a bight and he said: “Damb!” what is this?" I’ve been handing these things out at community meetings and stuff and they are a huge hit. So make a note of it. Mariana is not just root stock, at least that’s the case of this version of it. One older woman said. “If I’m about to be executed and am having my last meal. I would want my last bight to taste something like this. This plum is the most delicious piece of fruit I think I’ve ever eaten.” God bless.



Ha that’s awesome! You sure got a winner Plum tree over there Marcus. Well done.


So glad you got a heap of plums. Gallons on gallons. Bejeezes! Is there anything better than plums? Hard to think of while you’re eating them.

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Well, I set out buckets full of flatwoods plum flowers under my Mariana plum this year, and the result was the same. Last year there many hundreds of plums on Mariana. Right now there are thousands of the. I’ve never seen so many little plums on a try. I’m sure it will abort most of them. I will have to. But still, putting P. umbelatta flowers in the yard works wonders when it comes to making Mariana fruitful. God bless.


You mentioned European plums don’t work in your climate. Where you located ?

I’m in SE Georgia. I’m in a hot and humid Hardiness Zone 8B, but it has been more like Zone 9a for the last 8 years. On account of the combination of heat and humidity, stem canker pressure is too high here for European plums to work at all. They are usually dead from stem canker within about four years. Asian plums don’t work either unless they are hybridized with North American species, and even then it’s iffy.

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Yes the climate doesn’t seem favourable at all. If the winters aren’t too harsh you can try something subtropical like guava I think