Thornless jujube

I visited the Raulston Arboretum in Raleigh, NC on Nov 5, 2017. They had a “thornless Chinese date” (Ziziphus jujuba var. inermis) loaded with what I thought were pretty tasty fruit. The fruit is a bit smaller than the Li, So and Sugarcane jujubes I’ve grown. These fruits were roughly the size and shape of the average table grape. But I actually like the taste of these fruits better than my jujubes. This tree was also much more productive than my jujubes have ever been. (Granted, my oldest jujube tree is only 6 years old, so maybe flavor and productivity will improve with age. But I’ve been disappointed so far.)

The tangy flavor of this thornless jujube fruit reminds me of some of the fruit I’ve tasted from the Indian jujubes often used as rootstock. I’ve found the quality of the Indian jujube rootstock fruit to vary quite a bit - from hardly edible to pretty good - but they’re still mostly seed. This thornless jujube had a much better flesh-to-seed ratio and also appears to be self-fertile since I couldn’t find any other jujubes nearby. The arboretum supposedly has a much younger So jujube planted somewhere, but I didn’t see it. I’m assuming the seeds aren’t viable. I cracked open ten or so with a pliers, and they were all empty.

Do any of you grow this thornless jujube? I couldn’t find much about it with just a quick Google search. I’m tempted to go back and ask to cut some scion wood this winter.

Here are pictures from the arboretum’s website:
https://jcra.ncsu.edu/resources/photographs/plants-results.php?serial=105814

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I don’t know anything about it except that it certainly is intriguing. Since you were eating fruit in November in North Carolina I don’t know that that’s much use for me here in Wisconsin though.

Kind of a pisser, I was actually in raleigh this summer

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you could probably ask the curator about taking cuttings from that tree to graft to your trees. Or maybe don’t even have to, since that specimen is huge and probably scattering branches all over the place during winter storms. I checked its provenance and it was documented to have been planted in 1996. Pretty big for a 21 yr old juju tree, basing on the pictures, as well as the 24’ height mentioned by the arboretum’s webpage.
btw, thornlessness/small thorns of cultivated jujus is often a trait exhibited mostly by older/bigger trees. Some jujus are thorny as young grafts or as young trees but as the tree gets bigger, the thorns get smaller

incidentally, am not too sure about indian jujubes(mauritiana species) being compatible with jujuba species. And if so, they might be too tender to be used as rootstoc when grown far from tropical conditions.

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The arboretum website says they allow licensed nurseries to collect propagules with permission, and I don’t have a license. But I was thinking it still might be worth asking nicely, especially for cuttings from such a big tree. I doubt most nurseries are even interested in thornless jujubes. Or I could look for fallen branches like you say. The tree does seem very healthy in a raised bed along with a fig and a feijoa on its south side.

I thought most grafted jujubes sold here in the US were grafted onto Z. mauritiana. I bought mine from Edible Landscaping, and they all sucker profusely. If I let the suckers get big enough, they produce small marble-sized fruits with a big seed surrounded by a thin, tart layer of pulp and skin.
Does that sound like Z. mauritiana to you?

I bought one jujube from EL on its own roots (Tigertooth), but pine voles chewed it off below ground level within a few months. I haven’t noticed any vole damage on my other jujubes, though - all grafted onto what I thought was Z. mauritiana. I’ve transplanted suckers to serve as rootstocks and have had success with grafting onto them.

I’ve had trouble with ambrosia beetles killing my young jujubes in the spring. We often get late frosts here in central NC, and I think that weakened some of my young trees and maybe made them more attractive to the ambrosia beetles. They killed my So, Lang and Sugercane and only my original 6 year old Li tree survived, but it’s never been very productive - I only got maybe 15 or 20 fruit off it this past year. Jujubes haven’t turned out to be as tough here as I would’ve hoped based on their reputation, but whenever I see a big productive tree like that one at the arboretum it gives me hope that some varieties might be better suited to our wetter weather and late frosts here in the southeast.

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am sure the arboretum won’t mind you taking a couple twiggies in winter. Of course it is always good to ask beforehand.

mauritiana is supposedly tolerant of northern florida winters, but not sure if will survive in north carolina.
would you have pictures of your rootstock? They are fairly easy to tell apart from jujuba. Btw, both mauritiana and jujuba may bear marble-sized fruits. Some wild-type jujubas also bear smallish round fruits which have proportionally big seeds surrounded by thin layer of pulp and skin.

here, wild-type suckers seem to be unpalatable to sowbugs, but seedlings of both wild-type and named varieties get devoured in no time. Seems like sprouts from suckers have some chemical/hormonal protection of growing from mature roots, while seedlings don’t have much protection.

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I don’t have any summer pictures of my rootstocks, unfortunately. And taking pictures now that they’ve all dropped their leaves probably wouldn’t be as helpful for identifying them. But it must be wild-type Z. jujuba then, because it’s certainly hardy here in Z7. I just assumed it was Z. mauritiana because the fruits are roughly the same size, shape, and color, and I didn’t know wild-type Z. jujuba looked so similar. Thanks for clarifying that for me. I appreciate the observation about sowbugs’ preference for seedlings over suckers, too. I have pine voles burrowing all over my yard, and if they like something, it tends to disappear in short order. I haven’t had any jujube seedlings to offer them, though.

My rootstocks are definitely Z. jujuba - no hairs on the bottoms of the leaves.

The Indian jujube is “distinguished from those of the Chinese jujube by the dense, silky, whitish or brownish hairs on the underside and the short, downy petioles.”
https://www.hort.purdue.edu/newcrop/morton/indian_jujube.html

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Do you think that tree at the arboretum could be growing on its own roots? Did you look to see or notice if it was sending up any suckers?

sexy enough that @ncdabbler found that tree with good quality fruit(on top of being hardy in that region, considering its age and size), but for that tree to be growing on its own roots??! Sure elicits lust and desire to make even lucifer blush! :grin:

if it is growing on its own roots, then forget about requesting for budwood-- tell the curator you’d gladly rid their premises of “weedy” suckers and that you’d do it for free :wink:

apart from the wild-type rootstock, that juju tree is the only one have come across with an actual subspecies.
wild-type rootstoc is often named Z. jujuba var. spinosa, whereas named varieties are merely Z. jujuba’s

as always, it is also possible that it may just be another wild-type jujuba with more desirable fruit than typical spinosa’s

The arboretum’s website has listings for each plant in their collection and specifies that this tree was obtained as a bareroot graft. So unless it was planted below the graft, it isn’t growing on its own roots. I didn’t notice any suckers - too busy admiring the abundant fruit, and tasting them. It’s growing along with several other smaller trees and shrubs in a large raised bed (approx 2 ft above ground level) contained in a low brick wall.

Just curious - are you interested in named jujube varieties on their own roots because they would be easier to propagate that way than by grafting?

Yes, that’s definitely a thought, although I like how easy scions are to mail and to obtain in general, and I can graft jujubes pretty quickly and reliably compared to some other species.

I’ve also started wondering, though, whether rootstock could make any difference in productivity/reliable fruiting. It doesn’t seem like a very likely theory, but I’ve seen or seen photos of or been given fruit from too many trees all around me that are very productive to believe that climate is to blame for the poor productivity of my trees. I feel like there has to be another variable at play (which may interact with climate.) Maybe it’s something like soil type that I couldn’t very well control. Maybe it’s related somehow to how trees are pruned. Maybe it’s related to pollinators. Maybe it has to do with fertility levels. I’m wondering about rootstocks, though. I’d even be interested in transplanting a sucker of a productive grafted tree, like from the demonstration orchard in Greensboro. Mike got me some scions from the Li tree there that I grafted last year. I already have a mature, fruiting Li, but I wanted to see if there was any difference in strains of Li, so I have a couple grafts of that tree growing now. But I wonder if there could be a virus that spreads from scion to rootstock and from rootstock to scion that’s affecting productivity? Growing the same strain of the same cultivar on the same rootstock would seem like the ultimate test for whether I could solve my productivity problems with genetics.

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Thanks for the explanation. I haven’t been growing jujubes as long as you, but I’ve had the same disappointing lack of productivity with Li in particular. And that makes the fruitful Li at the cooperative extension orchard here in Greensboro all the more intriguing. I can run by there and see if I can find any root suckers to dig and bring you on Thursday. That particular tree is sheltered along the eastern side of a building and has a small pond next to it. I’ve wondered if those are factors in why that tree is more fruitful than mine, even though jujubes are supposed to be drought tolerant and able to handle colder weather than we typically have here in zone 7. It’s a mystery!

You make me wonder if maybe it’s not how much or how little moisture they receive exactly but something to do with consistency vs. fluctuations in moisture levels. It’s definitely a mystery to me still.

My Li seems to abort a lot of fruit - some pea sized, and others full-sized - they just shrivel up and drop off. Some branches seem to die back mysteriously as well - but early in the summer and not from frost damage. Maybe it’s lack of consistent moisture - I don’t know.

Jujubees are drought tolerant, but my impression is what they’d really like is a straw

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i too feel that some of our cultivars here would be more productive(sherwood/ga866/gi-1183) if irrigated with a fireman’s hose.

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