The Prague Chimera – What We Know So Far and Our Experiments

Added: 2026-06-04

[00:00:01]the Prague Chimera.

[00:00:03]Now, this is a plant that has received a lot of the spotlight in the hearty citrus community, and honestly, guys, it's pretty welld deserved. Now, it does have some notable downsides, but really in this video, I want to talk all about the Prague Chimera. Especially for those of you who are kind of looking around all over online and trying to find out everything you can about this plant, this will be a good video cuz we'll kind of just give you a basic summary of what the Prague Chimera is, what I've learned in my short time growing it, and really anything else I have to share about it, including some of the experiments we're doing with Intertocks, which this video will kind of serve as an update for you guys, too, who have been uh keeping up with that. I know I posted on the tropical fruit forum about it. So, this will be a a good kind of video to touch on that stuff. But if you know or don't know, it's in the name. The Prague Chimera is not your typical cold hearty citrus hybrid, which a lot of them are hybrids between the uh Trifogia Orange, a kind of very primitive and extremely hearty citrus, and you know, a conventional citrus or a dessert quality citrus. So the Prague chimera is truly a percl chimera uh between a satsuma mandarin, one of the most delicious dessert fruit out there, and the trifogia orange. Now, this is interesting because obviously because it's a chimera, it doesn't behave like a hybrid would. It's actually really interesting. So in this case, it's kind of like this freak combination where the vascular system of this plant is the trifolia orange. So the blood running through it, the core structure of this plant is trifolia orange. And you can actually see a lot of that influence, the larger thorns, the kind of, you know, more wild looking growth in a lot of areas. But as for the rest of it, those uh flowering and fruing portions especially in the the leaves, that is satsuma mandarin. And it's really kind of odd because if you think about it, and I know a lot of people have wondered this and and really question this, um, the satsuma portion, regardless if it's a chimera or not, it shouldn't really be able to survive the temperatures that the Prague Chimera does because these plants here in North Carolina, they shrug off 10° F, even as smaller plants, which honestly is challenging for satsumas and especially small specimens.

[00:02:32]They could totally die. But we have people as far up as New Jersey, so the northeastern coast of the United States growing the Prague Chimera and I've seen evidence of it fruing in Maryland, which, you know, these are areas you would not expect to grow citrus, let alone dessert quality citrus like satsumas. So, it's a really exceptional plant in this hardiness, but it it's kind of unusual because again, it it shouldn't be able to survive this under normal circumstances. So there's different theories as to why this occurs, but from my basic understanding, the Prague chimera, the trifoliate orange half of this plant seems to influence the satsuma half on some sort of uh perhaps chemical or metabolic level. So it definitely changes something in how the satsuma behaves and reacts to the colds uh where it allows those cells to again survive kind of supernatural amounts of cold uh for a satsuma mandarin. And I just want to show you you can really see that satsuma influence too cuz again I I know I mentioned it looks a lot like trifoliate orange but also looks a lot like a satsuma too because a lot of these leaves are very citruslike. You could see a lot of them are gloved and fingered kind of like trifoliate orange.

[00:03:51]But kind of look at the habit of all these plants too. I have uh a couple satsumas in the greenhouse and one thing I noticed especially about the one on trifoliate orange roottock the uh the frostari. It has a very kind of weeping habit to it. I'm sure some of you guys have noticed too if you're growing satsumas. But look at all these trees. I mean we have over a dozen of the broad chimera growing here. A lot of these are just on trifoliate orange rootstock and they're all actually rather low trees.

[00:04:18]Most of these I think are going into their second year, maybe a bit more than that, but they're at least uh 2 years old, I want to say. Um, and they're very low to the ground. This was our tallest specimen, but that's because we had it uh growing in the greenhouse and it was very vigorous and it ended up actually uh taking some damage because of that.

[00:04:38]But you can see really across all of these plants that influence from the satsuma mandarin. I I do believe actually it's it's probably majority satsuma, but that again that trifolia orange vascule seems to be really really key uh and important here. And for those of you wondering and maybe you're you're still on the fence like, well, is this really a chimera? How do we how do we really know? Sure, it produces pure satsuma fruit. Sure, it could survive down to like 0 degrees Fahrenheit, but that isn't necessarily proof.

[00:05:13]Well, I'll tell you, I've actually posted a YouTube short that you might be able to check out, and there is photo evidence of this occurring online. I've seen it happen both ways where you will have, let's say, this this new growth up here, right? This is obviously still true to type, but I have seen at the bud, especially if there's bud damage, that bud can split into one of the two halves. So, you can have it grow either purely satuma or purely trifoliate orange. Obviously, in the case of purely trifoliate orange, it'll be strongly trifoliate. The growth won't be weeping as much and the fruit will not taste good. Now, if it's pure satsuma, it is at that point unaffected by the trifoliate orange. uh at least to the extent where it's not much more than a roottock for it. So that satsuma portion will then die if exposed to really cold temperatures. This kind of combination really only works when they are in that arrangement where you have those those different tissue layers working all together. And now I have uh included the fruit on our hearty citrus taste test series and I can tell you guys 100% the fruit are exactly like a satsuma. If anything, the specific strain that was used is actually really sweet. It's not very acidic at all. Uh, and that actually brings me to the point. I should tell you a little bit about the backstory of the Prague Chimera, just because you might be curious. I don't know at all. Again, tropical fruit form is a great place to go for this information because there's much more knowledgeable people than me when it comes to this. Uh someone actually posted a lot of the history about this, but really from my understanding the Prague Chimera was this uh well part of a series of experiments where the Soviet Union was trying to I I I suppose have like their own commercial citrus industry in a lot of these colder regions that couldn't really grow citrus. So we s we see all these interesting uh texts about citrus being grown like almost uh beneath ground level and trenches and all these neat methods kind of sprawling on the ground.

[00:07:16]They had some really creative ways of getting these trees through the cold, but I guess at one point they were experimenting with these and trying to splice or however you look at it, uh, the really hardy varieties like the trifoliate orange with the, you know, commercial dessert citrus and try and get something that has the best of both worlds, which truly it does, but it has limitations. And that's what they discovered when they planted these out in mass and they were trying to have commercial groves of the Prague Chimera.

[00:07:48]Um, and unfortunately they it was met with disappointing results because these trees are generally really shy bears and I'll kind of get into uh the reason why, but uh especially after really cold winters too. It was actually noted some of the trees reverted back to trifoliate orange I guess at a higher rate. So they obviously they do still have a threshold and if it if it passes a certain threshold say it goes below zero substantially below zero uh just the trifolia orange portion will respout.

[00:08:20]But again they had whole groves of these trees and they were getting very little production. We're talking a few fruit per tree and in even colder regions it can be less than that. And now that's a big big downside to the Prague Chimera and something a lot of you will encounter if you're trying to grow it in colder regions. Now, granted, I've seen people have success both in the Southeast and the Northwest in the United States, as well as many people in Europe. It it seems to mostly depend on how mild a given winter is, how productive your tree may or may not be.

[00:08:52]Of course, in addition to it being, you know, fully mature. Uh, but it's it's kind of a weird weird situation here because it seems like the milder the winter, the more productive the Prague Chimera is. But the whole idea behind trying to grow such an interesting chimera is to be able to produce fruit uh despite having extremely cold winters. You guys see what I mean? It's kind of uh interesting that that relationship there because it obviously it's not really something you want. We want these trees to be fully productive no matter what because they and often times we need them to endure that cold.

[00:09:29]But I've seen instances of singular plants that were in pots and maybe protected on a patio or they were wrapped with Christmas lights and protected and those trees were very very fruitful. Or if you just got a an extremely mild winter, which we can get here, I'm sure one year I'll see these all loaded with fruit just almost like a normal satsuma, it's actually pretty unbelievable when these do load up. Uh, Sweet Home Alabama Homestead has a video where he he was showing off his Prague and all the fruit on it and harvesting them. I actually managed to get a few of those fruit for our our taste test video, but it it was incredible how much it loaded up because it normally doesn't. Normally, these trees are pretty sparse in terms of production.

[00:10:11]Like I said, you know, one, two, a few fruit on a whole tree. It's really not a lot. And I suspect the reason for that is, and if you haven't put it together already, it's the fact that the satsuma portion, while it is given this supernatural hardiness, uh, it isn't actually it it's too stressed by those conditions. So, under normal satsuma friendly conditions, it seems to be more productive. But when it's going through winters that satsuma could not normally survive, yes, of course, the vegetative tissues here all still make it through these winters. Um, but they're not uh they're not really holding fruit, I should say, because they will bloom profusely like a citrus often does when it's stressed uh and attempt to set fruit and most of those fruits will drop. And you also get a lot of deformed flowers where, you know, things aren't just fully formed correctly and you're not you're not getting a good, I guess, female portion. Uh, and thus it's not pollinating correctly and it's it's not setting fruit and and more importantly holding the fruit cuz the Prague Chimera actually can go through two periods of bloom. I showed you guys uh at the beginning of the video, we do have some blooms coming back here. It'll bloom in the beginning when it's when it's first growing out and then now it's kind of doing like a like a June bloom which is really interesting. I mean it'd be cool if it did set fruit but these fruit are going to ripen a bit later kind of going into November, December probably. So uh that is certainly uh a limitation here.

[00:11:40]But it's it's our biggest struggle when it comes to the Prague Chimera is lack of production and lack of production due to the cold. So, it can survive the cold. Uh, but getting it to produce is the hard thing. So, it's kind of variable. And, uh, I I don't know where that threshold is, if it's still willing to produce after extremely cold winters and it's just not a lot or it's truly directly related to the temperatures it experiences. So, that's actually something I'm looking to uh, study about this. But, we we kind of talked a little bit about the history, kind of how the Prague works. I want to show you something interesting which is some seedlings of the Prague Chimera which are over here. I have two of them that I have kept. There is one that I called because it did not seem to have the qualities I'm looking for and I do have to be a bit harsher with our limited amount of space that we have here. Both of these seedlings actually come from Sweet Home Alabama Homestead. Uh and it the these are very interesting material.

[00:12:41]These are one of several examples that I've seen where the Prague Chimera produces hybrid seedlings. Now, wait a minute. So, if the flowers and the fruit are Setsuma and let's say, you know, the the tree, the vasculature is trifoliate orange, how could it possibly be producing hybrids? None of the flower organs should be trifoliate orange. And yet, it appears that might be the case.

[00:13:06]It's kind of weird. I know satsumas in general deal with a lot of fertility issues from what I've heard. I'm not an expert on it. Um the Prague doesn't seem to struggle too much when it forms flowers correctly. Um and that seems to be more the downside here, but I don't know and I've yet to confirm and obviously many people have mentioned to me experiments I could do to confirm. So it may not be a while it may be a while before I actually find out what's really going on here. But again in multiple instances these fruit are self or these flowers are self-pollinating setting fruit and essentially they contain hybrid seed. So this you guys saw the Prague chimera up close pretty clear.

[00:13:52]It's kind of tormented looking. It doesn't know what it wants to be. It doesn't doesn't grow very pretty. And these ceilings here, num number two and number one here, we're calling these the Sitsuma wall, kind of named after him there. Um, you can see just how different these look. These actually look like hybrids. You can see number two looks like a catanderin or sitsuma.

[00:14:15]The these are sitsumas basically because it's a satsuma, but you get the point.

[00:14:19]Um, these look very typical of a 50% hybrid. Now, this one, interestingly, while it could still look like a 50% hybrid, it actually starts to look a bit more like an F2 hybrid or a 25% trifoliate hybrid cuz look at how unifoliated it is. And it actually has a good aroma and taste to to the leaves, you know, the foliage here. And it's it's not as hardy. There's a bit more pitting after the winter. It actually seems similar hearty similarly hardy to our Thomasville which kind of took some similar damage. So I don't know if it's in that like 5 to 10 degree Fahrenheit range which isn't very impressive for a catander which really makes you wonder is this a self pollinated hybrid between the two halves or is there some sort of weird genetic transfer stuff going on here that we don't quite understand. Now there are instances of this happening with graft hybrids where you know two plants are grafted together and the seedlings um produced while they they should really just be the scion variety they actually end up showing traits of the rootstock which is very unusual but if that could happen with these graft combinations who's to say it can't happen with a chimera so truly I can't rule it out uh I have suspected it's just pollinating itself but it it really Makes me wonder when I see seedlings like this that look so much like the satsuma. I actually did a video last year where I showed this tree and as you can see it's extremely vigorous. I I'm starting to propagate it cuz I have really high hopes for its edibility. Um but when it was growing really vigorously the leaves were big and rippled and extremely satsuma like almost indistinguishable when you had these really strongly uh monofoliate leaves. But a lot of the leaves on our citrus this year are kind of shrunken from the drought that we had this spring. So this isn't the best representation. But honestly, so this being number one and this being number two, number two does still look very attractive. But I noticed the leaves didn't quite have the same uh taste and fragrance as number one, which leads me to believe this isn't going to taste as good. Also, not to mention, it's a hardier plant. So, the relationship between the leaf taste and the cold hardiness and what the future fruit quality may be like on this plant, I have reason to believe this won't taste as good. But, I can't rule out that it won't taste okay and it won't be useful to someone cuz if if this is a fairly hardy sitsuma and produces better fruit than other sitsuma in circulation, which I haven't heard great things about like the I think the they call it the citrine or something. Haven't heard great things about that one. And that's a satsuma trifoliate cross. You never know. If we have something better than we have already, then maybe it's it's worth saving. But I'm not propagating much more of that one quite yet. I'm more excited about this one, even if it's less hearty. I'm all about looking for those really good orange substitutes right now. But that's kind of a tangent there. I did just want to show you guys.

[00:17:21]So, it's really weird what goes on with the seedlings here. Uh coming from these again odd chimera type of plants here.

[00:17:30]Now, I mentioned the struggle with productivity, which is exactly why I've begun somewhat of like a miniature inner stock trial here. I don't have a whole lot of space to be doing crazy trials just yet. I may have some space to do that in the future. Uh, but for now, I I fully intend on all these plants growing out to full size in this yard on these different inner stocks. But I'm very curious to observe them in the long run cuz I did want to update you guys. You'd seen these already. we are noticing some differences between them. Uh especially with one in particular, but basically the idea behind this is these are all on trifoliate orange roots. I have the most trifoliate orange roottock and it's at the best size for grafting. So that's mostly what I use. But I had plenty of cyan wood to do intertocks, which if you know anything about intertocks, they do still exert an effect on the scion, just not to as great of a degree as a roottock. But I figured that might just be enough to get some sort of influence on the scion on the the Prague Chimera Scion and uh see if we could do anything about the the growth, the health, the productivity uh of this hardy citrus because like I said, these are kind of oddlooking trees. They're not very productive. If we can, you know, address anything about it, improve it in any way, I mean, that's that's better than where we're at already. So I'll I kind of go down the line here of these different inner stocks and and how they've been doing. I believe this first one here closest to the rest that are on trifolia orange roots. This is on a swingle inter which is really cool seeing these grown up now. So you can see I did a side veneer graft there. And then this was a chip bud graft onto this was a swingle scion right here. And now you can see in one season. So, these were grafted last spring, summer, I think summer, and um it's put on a lot of size for one year. The Prague is a slow grower. And you guys have seen from the onegon trees we've had, it takes a long time to size these up and make them look substantial cuz even at their onegon size, they look kind of wimpy.

[00:19:36]It's just how these plants grow. But this one is definitely a fine specimen for the amount of time that it's been growing. So, I could say the swingle does seem to have sped it up perhaps a little bit, especially given when these were grafted, but I'm not noticing anything too crazy. It does still look pretty typical. Uh, it did take some light light damage, but these were very small plants and it was a very harsh winter, so I I'm pretty understanding of that.

[00:20:03]Next up here, I want to say, and if I have it labeled, I think this was Yep.

[00:20:08]This was the five-star intertock which you could see there. Pretty cool. This one split out into uh multiple branches from that chip bud graft. And there is our kind of ugly looking side veneer graft with all that callus there. Uh but this one's doing pretty good too. It actually branched out a bit differently, but it's growing really well. It's not a crazy looking specimen, but uh similarly to the Swingle, I notic with both the CitroLoss, they seem to take just a tad bit more damage. Nothing crazy. some light burns, some light pitting. Uh but again, that could make the difference to where I wouldn't recommend doing this for, you know, like a zone 7 climate cuz we're we're considered zone the beginning of zone 8. And what I can get away with, you may not be able to get away with. That kind of goes for a bunch of things. Hardiness ratings, different roottocks. It works differently depending on your climate. Sometimes you got to try for yourself. Next up here, now this one seems to have grown quite a bit more than these CitroLows as you could tell here. And I'd heard that this one made a very vigorous roottock uh for Rare Grows New Jersey. And um I'm seeing as an inner stock, it's kind of doing a similar thing. This is Titry. So we have same thing, side veneer chip onto the tit scion. And now this tree that's branched out. You can see this is actually a smaller roottock, too. And yet it's got a ton of top growth. If I want to be real scientific, I'd chop these all at the graphs and uh weigh out the amount of vegetative material. But I like these trees. I'm keeping them. So, we're not going to do that. But just interesting to see that. Uh probably the worst one, and I don't know, this could be the circumstance, too, of it. It was one of the latest ones and it is on a smaller roottock. So, I'll be forgiving of it right now because normally, well, this is X639, the inner stock. Normally X639 is a very vigorous roottock. Uh, so I'm going to give it some time and kind of see how it does in the long run. But not noticing anything too crazy going on with this one. Looks pretty all right.

[00:22:10]Looks pretty standard. A little bit of pitting, nothing crazy. Tie try so far in the lead for probably the best looking inner stock combination. You can see here too. I mean, this was actually So, there's the side veneer graft.

[00:22:23]There's the I think it was a modified cleft graft. We got some of the some of the inner stock sprouting there. That's something you got to watch with these.

[00:22:31]Um, this was actually a cutting of X639 that I rooted and then I think I ended up chopping that cutting up and using it for this. Uh, hard to explain. I think I just at the time that was the best material I had and whatever. So, we we ended up using a a rooted cutting for the inner stock. It was kind of funny, but we'll see in the long run what this one does. I don't want to be too judgmental of it. Again, it's not super scientific just yet, but in over the long term, we should definitely notice uh if there are substantial differences.

[00:23:02]Now, here's the one where you can see I had to stake it up because it grew way more than I expected. I noticed a huge difference with this one. And you you guys actually might remember last year I auctioned off a Prague Chimera on this as a roottock and it was a pretty popular auction actually and I have one other of these trees on this specific inner stock that I may auction off this year. I debated kind of planting it out somewhere but I have so many already where I may just auction off for you guys. But this is US 942 as an intertock.

[00:23:36]And this one was actually a really tiny one. If you could see there, that was, I believe, some sort of cleft graft with your chip bud graft there. And this one just grew absolutely incredible.

[00:23:53]This was our smallest one last year. It was on this old roottock that grew up here, and I wanted to make use of it cuz I was like, man, you know, I don't have much material, but I really wanted to add this inner stock to the group. So, this was also one of the last ones, which you know, X639, maybe that's saying something. But again, subpar roottock, but we made use of it. It's growing bigger now. Um, and the inner stock was actually quite small. This was done later. And it grew this long kind of whip the first season.

[00:24:25]And then this year after the winter, which it took very little if any damage to the main stem, it just flushed out intensely. And not only that, the leaves look healthier, greener, more abundant.

[00:24:39]It's actually one of our fullest looking Prague chimeas, which has me wondering. I mean, the US 942's really proven itself as a as a roottock. It's an excellent choice. Very easy to root, very easy to graft onto. A lot of varieties are compatible with it.

[00:24:56]And now, just as an inner stock for the Prague, it's doing fantastic. There is a visible notable difference as you can see with the US 942 inner stock versus everything else. So, for all I know, this could end up being our healthiest tree out here, which is is really really crazy to see a difference that early cuz I was expecting subtle differences like with the tie tri. It seems to be like our second best combination here. Citrallows are still good, but perhaps there's some delayed dormcancy or something going on that leaves them a little more uh susceptible to the cold. But truly, US 942 may be a very optimal uh at least inner stock, if not roottock, depending where you are. So, if you're in a warmer zone that's still a little too cold for satsumas, this could end up being a good choice. But we're gonna kind of show you guys on this channel with time just how well this does and how importantly how productive it ends up being. So I'm really happy that's making a fuller healthier tree, healthier Prague Chimera here. But I want to see if that produces even better. And my theory behind that is if it's a healthier tree, you know, if it's doing better overall, I wonder if it'll be less stressed. it won't go into that whole stress response and bloom and then drop all the fruit and instead it might hold on to more fruit. So, it's kind of a far-fetched theory, but it's just again it this is compelling evidence that it's doing something. Now, will it do what we want? I don't know. But again, we also have several other roottocks that we or inner stocks that we could prove this with and see if they're actually exerting some sort of influence on our scion variety, the Prague Chimera here. Can't wait till these flowers open. Not setting my hopes high for fruit this season because, you know, we just transplanted these to the new property. But, uh, overall guys, I think that's pretty much all I have to say about the Prague Chimera. Uh, let me know in the comments if you have anything additional to add about it, if you're growing it. Uh, and, you know, just let me know your experiences, your advice when dealing with this. Uh, I don't think anyone quite knows how to get this thing to really uh, fruit more.

[00:27:12]You know, the the Soviet Russians couldn't figure it out all that time ago. It's made its way to the United States and we're still trying to figure out this this puzzling plant here. Um, but it's really cool. I I totally understand why this one has the spotlight and it has for quite a while.

[00:27:30]Uh, it's our best seller uh for the nursery and we can hardly ever keep up.

[00:27:35]Um, and again, I understand it's super cool and I I don't know. I Well, shoot.

[00:27:42]Let me show you guys. I wasn't going to show you in this video, but who am I kidding? We're already here for half an hour, right? So, here we are in the greenhouse. I have some experiments.

[00:27:52]Now, I'm not going to show you. I I'd have to unwrap them to really show you, but I am back to trying this year at creating my own chimeas uh with other edible citrus varieties. Um the two that I've used so far cuz I had good size wood and they they may have traits that I'm looking for, I've used myer lemon and chang mandarin uh with the trifoliate orange. So these are the chang ones and as you can see there, we have these fully wrapped graphs going on. And basically what I was doing is I was taking the stem. Here's an easy stem to look at. I was taking the stem of the changer lemon, splitting it in half at the bud there, and then grafting each half under a bark flap, lining it up with the cambium layer of the trifoliate orange. So you can't really see all that going on in there, but that's what I've been doing with these. And I think this may create the right conditions to induce the formation of a chimera. I'm not exactly sure, but I got to try something because I've mentioned this honestly at this point for years now and I just haven't had the time to devote towards this. And this year I'm getting serious about it, guys. Uh especially after our maybe possibly seeming likely Fingerlime Chimera that happened by accident. I want a hardy one and I want one that's better than Prague. So, I'm pretty determined with that, guys. We'll see how that goes. Uh, oh, I forgot I did do one with a citral and I think I did bloom sweet. No, I did carara on that one. So, I don't know. That might be an interesting one. But anyways, guys, those are my experiments. I encourage you guys to try as well. I've shared a lot of my thoughts on the forum about creating our own chimeas and, you know, seeing if we can recreate the circumstances that led to Prague.

[00:29:43]There's multiple documented instances of this happening. So in numbers, if we're all trying at once, some of us got to come out with something as some of us already have by accident. So we just need to do it with intention and actually try and make something that's hardy. I think we we we could see some really really cool stuff in the coming years. Not just hybrids, but true hearty citrus chimeas, which I have a lot of faith in that idea. I don't know if they will suffer from the same problems that uh plague the Prague. Um, but ideally we can fix some of that. Perhaps some varieties don't get stressed as much under these same circumstances because again that's what I suspect. I think it's the whole stress response and then they're just not fruiting very well as a result. But let me know your thoughts.

[00:30:30]That's enough. This we'll consider this uh a spotlight video uh for the Prague Chimera much like we did the Trifiola.

[00:30:37]Uh and that should really touch on most of what you need to know. But if there's anything I didn't touch again, let let me know or check out the website cuz I could have missed something that we have uh in our post section on the malberries.org.

[00:30:50]But otherwise, thank you guys uh for joining as always and I'll see you in the next one. Bye-bye.