Jujube fruit set if you don't have hot dry summers

[disc4tw]

As has been postulated before, it seems to me just from reading through the forum that the particular cultivar may play as big a factor as soil moisture etc.

That being said, I have to ask a few questions.

1. Is it possible (has anyone checked) that jujubes developed different ploidy similar to apples etc (diploid vs tetraploid) which may make it harder for specific cultivars to set fruit?

2. Do we know whether specific cultivars were bred to succeed in certain climate zones? I know that @scottfsmith has extensively trialed apples and other fruits to figure out what works.

3. Jujube trees themselves may be less finicky than apples as far as disease and growing conditions go, but is it possible that for fruit set there are a host of variables at play that have a great impact?

I may have missed the answer to some of these questions but they seem like important ones to ask/reiterate.

[castanea]

There are definitely jujubes in China that come from northern areas, that come from dry desert type areas like New Mexico, that come from areas like Tennessee, and from more southern regions like northern Florida, but we don’t always know where jujubes being grown in the US originated.

[castanea]

This is an old photo of “Globe” jujubes. These are very pretty jujubes, but also the most tasteless jujubes I have ever grown, even worse than Lang, but I grew them in the California central valley. Jujubes can develop different flavors and sugar levels when grown in different climates, and Cliff England reports that they taste good for him in Kentucky, so if you’re in a humid climate you might want to try growing “Globe”.

[Robert]

I put in four more jujubes earlier this year. Two of the Honey Jar are coming straight out the gate putting on fruit. Meanwhile my old freeloading Li is once again wasting space.

@mamuang is correct. Honey Jar is THE east coast jujube. What would be claimed as the #2 east coast jujube? Sugarcane?

[BobVance]

@Robert

What would be claimed as the #2 east coast jujube? Sugarcane?

If you want a common variety that is reasonably productive and tasty, then Sugarcane or So.

Possible better (but harder to find) options for productivity (and still pretty good fruit): Bok Jo and Xu Zhou.

Black Sea, Massandra, and Russia #2 are all good quality, but I’m not sure if they are more productive than Sugar Cane (more observation needed…).

Russia #4 is very productive, but not very tasty.

[Robert]

Thinking my jujube collection will stop here. NEW jujube prices have risen to out of control levels. Might be time to learn how to graft to increase the collection.

[BobVance]

No reason for it to be either-or. You can add more and graft the harder-to-find ones over laggards like Li. I’ve been doing both, though eventually I hope to have my potted seedlings and suckers big enough to plant out. Much cheaper that way, but it takes a long time to get them that big.

[Kate6b]

I am in the same boat as you. I will have to learn grafting. Now reading the comments above, I have to get honey jar.

[k8tpayaso]

You are where I was when I joined this forum…. I had never even considered doing anything like grafting. Next thing you know you’re addicted!

And it is amazing fun, gives you a feeling of satisfaction and accomplishment, makes it easier to have a wide variety of fruit, and impresses your friends that you can do it!!!

[snowflake]

@k8tpayaso

impresses your friends that you can do it

My uncle is a doctor so I showed him some pics and said “I perform surgery too!” Of course he said “That works?” If only on humans!

[BobVance]

I noticed something interesting today. Two Honey Jar trees at rentals which had a lot of fruit late last fall (later than you would expect from HJ) seem to be doing the same thing again.

Late last August, the fruit was just forming:

Some ripened starting in mid-October and most/all was at least somewhat ripe by the end of the month when the first frost came. Fruit size was smaller than normal, and it didn’t have the full sugar level (though still plenty good to eat).

This year, there was a ton of bloom in early July (7/1):

But, there was almost no fruit-set. There are probably 5-10 fruit in the entire tree from that time:

But, interestingly, it seems to be happening again. There are now a bunch of small fruit that are forming, just like late August 2020.

Now, you could argue that maybe this is just an unusual variant on Honey Jar. But, a Bok Jo graft on the same tree (grafted this spring and now ~4’ long with lots of side-branches) is doing the same thing, forming new fruit late in the season.

Also there is 2nd HJ, at a different rental (different town even) which seems to be doing the same thing. At the same time, there is a 2nd HJ at the same site (maybe 30 feet away) which is covered with an early crop which has sized up already and will hopefully be ripe soon.

Even though the first tree is just setting now, they were already sizing up in late July on the 2nd tree at that site (7/29/2021, other HJ at site):

It’s a bit of a puzzle…

I wonder if part of it is a bit of a hangover from last year. Ripening fruit right up to the frost could put a bit of stress on the trees. One of the 2 late HJ trees had some dieback (lost a couple big scaffolds), though it has grown well. On the other hand, I suppose it is possible that the same conditions which caused it the first time, did so again…

I think part of it could be vigor vs fruit set. Just last week, I cut back one of the HJ (the one at the vigorous site, without a 2nd HJ), which had grown to 14 feet tall. I cut it back to 10’, right before the tropical storm hit last weekend. Which means it probably put on 5-6’+ of growth this year, as well as sizing up the Bok Jo graft very quickly. Maybe all that vigor delayed the fruiting until later in the season. The 2nd HJ at the other site (the one which set early) is only a 4-5’ tall spreading bush, so it put the energy into fruit, instead of growth.

Which brings me to another possibility- maybe it is excess water which jump starts things. Last year, there was a big storm in August (maybe 2nd week?), right before they started to set fruit in mid-late August. And this year, we had the already mentioned tropical storm last weekend, followed by 4 days hot days (~90 each day and mostly sunny).

[cousinfloyd]

I just got a review of Bok Jo from my teenage son I thought I should share: “Che fruit is better.” And he likes jujubes a lot, especially Li and the first couple fruits he’s gotten to taste from Black Sea but also Lang, Redlands, Honey Jar… I have similar feelings about Bo Jo, actually probably more extreme than my son. My son will take Bok Jo fruit if I offer it to him (but he’ll also eat che fruit); I’d mostly prefer just do without Bok Jo fruit altogether. I feel like I ought to force myself to keep sampling the fruit just to get a better feel for it, because it has been very productive this year, but having eaten four or five fruits this year I find myself not even wanting to sample it. My one tree that I grafted two (?) years ago has been super productive this year, though. Last year it set a huge amount of fruit but then aborted most of it before it ripened. This year it set a huge amount of fruit but it’s also ripened its crop. But the fruit quality is the same as last year. Maybe there’s hope that the quality will dramatically improve with age. Or maybe it would be good for some use other than fresh eating. But the quality is just really poor. I wouldn’t say there are any off flavors but there’s just nothing there to appeal to me. It’s definitely not sweet, and it’s not appealing to me as a sour fruit either. The size of the fruit is average to maybe a little below average for a jujube.

[ncdabbler]

@cousinfloyd

“Che fruit is better.”

Ouch! It doesn’t get much lower than that, does it?

I grafted Bok Jo to a couple of my established jujubes this past spring, and the scions were precocious and bore a handful of fruit for me. I thought they tasted pretty good, especially for a new graft. The texture wasn’t as crisp as I’d like, but I thought the flavor was fine. They were very sweet too. It seems to me that some jujubes taste better before they are completely brown (i.e., Honey Jar, Li) and others taste better once they have completely changed color (i.e., Cliff England’s Autumn Beauty, the less tasty version of So). I assume you’ve probably tried Bok Jo at all stages of ripeness and found it wanting. Maybe there are multiple versions of Bok Jo in circulation?

[JustPeachy]

@tonyOmahaz5

I want to do an experiment by using a hose clamp and tighten the screw over my jujube and persimmon trees to have a girdling effect without having to scorching the trunks. What are your thoughts?

I wanted to post this since it seemed relevant. I noticed this as I was searching around Baidu. They do this to save on labor costs and make it easy for all workers to access.

[JustPeachy]

@BobVance

Zang Huang Da (my wife translated the “Da” part as meaning “Big”, but wasn’t sure about the rest- possibly a location):

Found it - the name belated though it may be. 赞黄大枣 - English name: zanhuang jujube or zanhuang dazao jujube. It’s suppose to be the only natural triploid in China. It’s an heirloom cultivar that seems to be eclipsed by newer versions in commercial cultivation.

@BobVance

Zang Huang Da (my wife translated the “Da” part as meaning “Big”, but wasn’t sure about the rest- possibly a location):

Your wife’s suspicions were correct. It refers to the local county in Shijiazhuang city in Heibei province. Looks like it has the equivalent of what might be considered a PDO protection.

[castanea]

@BobVance

KukJae 1 Ho

Have you had fruit on KukJae 1 Ho?

[BobVance]

@castanea

Have you had fruit on KukJae 1 Ho?

Sorry for the slow response. I was going to check to see if I could find the grafts, but it’s been cold and the few times I’ve gone out I’ve forgotten. I’ve never gotten any fruit from it, and even though I had 4 successful grafts per my records from 2017, I don’t even know if any of them are still alive. 3 of the grafts were to rootstock suckers and the 4th was to a tree which hasn’t done all that well, so it wouldn’t surprise me if I lost the variety.

[castanea]

I understand. From start to finish, that sounds like something I might have written.

[BobVance]

I was reading a page about jujube from Australia (I thought I may have bookmarked it from here, but I can’t find it with a cursory search).

https://www.agric.wa.gov.au/minor-fruits/jujubes-western-australia?page=0%2C5

Measures to improve fruit set include:

• trunk girdling during flowering
• heading back current year shoots
• keeping bees in the orchard during the flower season
• two to three sprays of 10–20ppm gibberellic acid or 0.2% borate during flowering.

I’ve tried spraying a bit of gibberellic acid, though this past year I think I was a bit late with it, as it was getting very hot and near the end of bloom.

The item in that list that I think is interesting is “heading back current year shoots”, as I think I’ve accidentally done that. Last year I got a big (and late) flush of fruit on a tree when I cut it back from 14 to 10 feet during the summer (maybe late July or early August). Next year, I’ll try summer pruning a bit earlier and on more trees and see if it makes a difference.

Edit, added pics…

The early crop on the tree was about 6 fruit. Here is a pic with 3 of those 6 ripe, along with the later crop, which set after I made the harsh pruning cut.

It took a while, but they eventually ripened. While some were a bit small, they were still quite good:

[jujubemulberry]

@BobVance

heading back current year shoots

pruning upright stems. If one is already planning to do that, would be best to do it nipping in the bud, literally. Postponing pruning of upright stems would equate to unnecessary wastage of rootstock food supplies, because young uprights are more stem than leaf.
Old upright stems are more leaf-than-stem since their laterals produce more of the herbaceous/leafy/flowering branches per node along their laterals’ lengths.
Young upright laterals usually only produce two per node.

the only disadvantage of removing upright stems is if there are lots taller trees/structures nearby(especially in areas with short growing seasons), that the only way for a juju to get more photosynthesis-time is to grow more uprights. So even with more leafy flowering branches, fruit set would n’t be great

a 5 foot tall juju that is close to a 6 ft tall fence will not get much sunlight compared to letting it grow taller and produce a canopy that overhangs the 6 ft tall fence instead of the other way around.

only then will subsequent pruning of uprights(while green) be advantageous.

btw, pruning uprights also prolongs viability of fruiting spurs/laterals