Jujube leaf size vs productivity?

General Fruit Growing
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Has anyone noticed a correlation between jujube leaf size and productiveness? I haven’t paid enough attention in the past, but I was looking at a multi-grafted tree today and noticed that the leaves on the Bok Jo branch were much bigger than those on the surrounding branches. Last year, the Bok Jo branch produced maybe 30 decent sized fruit on maybe 20% of the bush/tree, while the 50%+ Sugar Cane made 6 fruits. Another branch (I think from the rootstock) made a couple dozen small fruits. 3 other varieties on that tree made no fruit, though 2 were newly grafted.

Bok Jo in foreground on right, with other varieties in background:

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For the last 2 years, the Bok Jo has been massively more productive than all the other varieties (on a per branch-foot basis) and I thought it was interesting that it also has the largest leaves.

I took some wood from that branch earlier this spring and grafted it onto two other trees. One of the places I grafted it also has very large leaves (at least the ones near the base of the stems- not the newly forming leaves). I need to check the other one tomorrow.

Here’s one I grafted (3 grafts at close to ground level) which is growing much quicker than most of my jujube grafts:

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The difference is very noticeable when looking at the tree, but I should try to quantify things (makes it easier to compare…):

Bok Jo: average 2.25" long, 1.25" wide
Sugar Cane (same tree): average 1.7" long, .75" wide

That doesn’t look big on paper, but as best I can figure, the Bok Jo has over twice as much surface areas per leaf (it’s a bit tricky, as jujube leaves aren’t uniformly shaped).

I checked some neighboring trees and none had leaves which were as uniformly large as that Bok Jo graft (made in April 2017). But, the Shanxi Li and the Sherwood both had some large ones, while the Li and the GA 866 were mostly small leafed. Those 4 trees were planted in 2016 in almost complete sun and have produced a total of 1 jujube (Shanxi Li a year or two ago).

Which leaves me wondering:
1.) Is leaf-size just an inherent quality of a given variety?
2.) Is large leaf size an indicator that fruiting is likely?
3.) If #2 is true, is it causal (big leaves being better able to capture solar energy) or correlative (healthy plants make bigger leaves and healthy plants tend to fruit more)?

Has anyone else noticed any patterns?

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the bok jo you gave me does have broad, apart from having a different hue and not as stiff as other broad-leafed jujus.

will try to answer your queries, but just from my observations:

  1. it is mostly inherent, though have also observed slightly smaler foliage on sugarcane that is planted at a sunnier/hotter/more arid location(especially if grown on pots)
  2. i don’t think large leaf size being an indicator. Except, of course when comparing leaf size of seedling vs. itself when older, or when grafted to a vigorous, healthy rootstock
    3)while broader leaves will be better at capturing solar energy, this is sometimes an adaptation signifiying a lack of exposure to sunlight

i actually grafted your bok jo on sugar cane and will post a pic when i get the chance. Sugarcane has smaller leaves than bok jo, so will see if the production is similar.

btw, the shanxi li and li that we have here–they both have relatively broad foliage. Same with ga 866. Jujus are just mysterious sometimes!

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Nice- you are replicating my setup in an environment with a lot more sun.

Though this month, we’ve had a string of mostly sunny days for the last few weeks. If it can continue for a bit, maybe I’ll get a good fruitset this year.

I wonder if some of my discrepancies (like GA866 and Li being smaller) could be due to the generally lower light level. Maybe Bok Jo has been so successful here since it can adapt it’s leaf size?

I started expanding it a bit, but if Bok Jo continues to standout in terms of production, I’ll have to start grafting it far and wide onto a lot more trees, as having so many non-productive jujube starts to wear on me.

That could indicate that stressed plants don’t get as big of leaves. At least when I take care of them, most plants in pots get some level of stress :slight_smile:

I’ll try to keep a closer eye on this- I’ve got quite a few specimen to look at and try to puzzle things out.

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@BobVance,
What varieties you grow that are not productive? Love to avoid those as your and my climate is so similar.

Mine is Shanxi Li. It has gotten grafted over.

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That’s the main issue I face here- most varieties aren’t productive, at least for quite a while. It is more noteworthy when something does start producing. For example, the So that I planted in 2011 started producing a bit in 2014 and a decent amount in 2015. That’s 3 seasons for some and 4 for more.

The fruit I got in 2014 was so good, that I started planting a lot more. At least trying to. I got 50 rootstocks from Roger Meyers in 2015, but I think there was too long of a gap between when he harvested and when I could plant, resulting in none living (as far as I know- I gave some of them away). Then, in fall 2015- spring 2016, I planted another 16 trees. 2 from Rolling River didn’t make it and 2 fall-planted So from JFaE got hit by cold immediately after planting and had to grow back from the ground the next year. But of the other 12 trees, I’ve gotten only a handful of fruit in 4 years (1 Massandra, 1 Shanxi Li, 1 from a Dae Sol Jo graft, and 3 Honey Jar). It’s bad when you can count your productivity in the individual fruits…

That means that even So (which I know can be productive here) sometimes isn’t. In addition to the 2 fall planted ones growing back from the ground, I planted a large caliper one in the spring from Sanhedrin, which still hasn’t produced at all after 4 full years.

And last year was particularly bad, in that the So which had previously been productive produced a very small crop. I think some of that could have been due to a long rainy period during the summer.

So you can see why having a variety like Bok Jo become almost immediately productive (the year after grafting) is pretty exciting to me and why I am trying to see what makes it so different.

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Bob,
Do all your trees in full sun?

My Honey Jar and Sugar can have been productive all along. Shanxi Li, same age, same sun, same teeatment is not.

Massandra and So, I think they were only 2 years old last year. I seemore flower budsthis year, we’ll see.

How are the trees from Dr. Yao’s?

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Most are in near complete sun. In built-up areas, it is hard to get complete horizon to horizon sun, but I chose places where they may only loose a bit of early morning or very late afternoon sun. Like half an hour or so. There are a few which have a bit more limited sun. None less than 2/3 of the day though. The productive So is actually a bit limited, in that it is shaded after 4pm. But it is still productive (at least on the South side), so sun can’t be the whole story.

After hearing about how you were fertilizing and getting good initial results, I started doing that. I think it was last year and this year. And this year, I’ve been watering them during the long stretch without rain.

I almost always have flower buds, even on notoriously stingy producers like GA866. They either don’t set, or don’t stay on the tree past a small stage. In the past, I’ve seen a lot of little insects around them. So I don’t think they hurt for a lack of pollination, especially given all the varieties here.

Nothing yet, but I’m still pretty optimistic about a lot of them (Alcalde #1, Fucuimi, Russian #2, Dai Bai Ling, Maya, KFC, Sandia, etc).

I also have high hopes for Massandra, as the one fruit I got from it was excellent. And the tree was relatively small (from OGW), so it has had a lot of ground to make up. Come to think of it, that is one that doesn’t have full sun- I should takes some wood from it and put it on one of the more established trees in full sun.

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@BobVance,
My Massandra was from Burntridge. A couple of the fruit I tried last year were very small and unimpressive. I got a not-tasty and-not- very contorted So from BR, too.

If this Massandra does not produce good quality fruit, it’d be two strikes against BR regarding jujubes.

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Bob, I admire your persistence!

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Well, I wouldn’t be so persistent if I didn’t have an example of what the upside looks like. How often do you find a fruit tree with great tasting fruit (among my favorites, but not quite up to top quality nectarines or sweet cherry), no need to spray for bugs or fungus, mostly ignored by wildlife (thankfully) and even valued by my wife (we bought 40 pounds of jujube last year at her suggestion).

It’s just a matter of figuring out how to make it happen. I’m growing so many of them, at enough different locations (rental properties), that I should be able to crack the code at some point. :slight_smile:

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bok jo is supposedly korean and with korea being a much smaller country in terms of land area than china, the koreans probably found it worthy of the square footage of land it occupies due to its productivity. Hopefully will get the chance to take photos or better yet, a video of your bok jo graft on sc tomorrow.

will probably do the same if i were you. Nothing wrong about being super-selective about your trees since jujus aren’t supposed to be productive in your location. The most consistently productive cultivar/s should make up the majority of your trees.

bok jo is quite productive here too. Have to say though that its foliage seem to be the most favored by leaf-cutter bees, being relatively soft.

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Everything short of GA866 is productive for you! :roll_eyes:

While it was super-productive (10X+ compared to my oldest/best So last year), I don’t think it was the best texture. Honey Jar and Sugar cane were just a bit better. Then again, when I said that to my wife, she looked at me like I was crazy and said “This one is great”. I guess she still uses the spongy ones from China-town as her baseline.

If that kind of production difference occurs again, I’ll need to get some others in the Northeast trying Bok Jo, to see how widely adapted it is in my area.

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gi-1183 and porterville are two other sparse producers here.

btw, bok jo was pretty good and crisp here when borne and ripened during milder weather, but it was quite mealy when borne and ripened at the height of vegas summers

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I’d believe that- I think I have a GI-1183 graft from Roger’s wood in 2015 on the big So, which has never fruited.

Bok Jo ripened near the end of September for me. I have a note from 9/21/19 that the first Bok Jo and the last Sugar Cane were picked that day. Bok Jo was crisp and good- just not quite as crisp as SC (I thought). But I look forward to comparing again!

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sc is crisp and juicy here, even at the height of our summers, but unfortunately has a noticeable bitterness ripened in hot weather
hj is pretty good, regardless of the high temps.

below is a photo that sadly does not do much justice. Summer glare is too much for my cheap celphone…
Anyway, bok jo is the larger-leafed bunch at left, while sc is the taller and smaller-leafed bunch at right

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