The Tropical Fruit Forum

Gotta say, making a list of cold hardiness in citrus seems very difficult. I personally wondered, since citrus are influenced so much from enviromental variables, how do you even compare the hardiness? To get a reliable list,  people should grow a BUNCH of different citrus, in rows, very close each other, on same rootstocks (ideally a dormant one, like the poncirus, so you are sure they are in same physiological stage when winter comes) under the same fertilization program, with plants of the same age. I doubt that something similar has been done, except maybe in research center, but still, research centers on citrus usually are in place so warm that some species aren't tested to the true extent of their cold hardiness.
The fact that i live in a place that has a proper fall, helps a lot with acclimation, and i think this may explain some discrepancies i see from here to the US.
Grapefruits, at least some of them, seem to be as cold hardy as orange if not more. I think a lot of people mix "heat seeking" with "frost tender". Grapefruit may need a lot of heat to make decent fruit but they don't seem bothered by frost. The only problem it's that you get acidic fruits.
Kumquat are really hardy compared to other fruit bearing citrus but fruits can be damaged from cold.
Lemons and oranges are on par. I see very sparse oranges there here, as much sparse as lemons tree.
Clementines are more hardy thank people give them credit to. I had one this winter that went to -7°C (my nights in winter last for 14 hours) with just frost cloth and it didn't even flinched. It is grafted on bitter orange. Ironically i had a tahiti lime planted very close to that plant, own roots. Some twig dieback but the plant didn't even die to the ground.

Woah, Laaz, that's a beautiful fruit.

Ilya,
glad you saw this. Hopefully I will be able to get a good plant in few years. I'm particularly happy to see that you plant managed to remain outside so long. I guess our climate are pretty similar judging from the other plants i see in the pics. I would prefer a little more "dome shaped" plant but i guess i can prune it in the shape i prefer. The fruits indeed look very nice. Do you know how much they can hold on the plant? The decorative effect isn't secondary for this one.

I think that's really hard to come up with anecdotal evidence if grapefruits are hardier than an orange. The reason of this is that while the relative hardiness may be in doubt, i think all of us agree that acceptable grapefruit need more heat than oranges; now, the places that in winter are colder, usually have also less total heat, so grapefruits aren't exactly a desirable plant there, and most probably got replaced, so in any given time there are few plants of grapefruit that are grown in paces where oranges can't.
The difference in anecdotal evidences may also be related to physiological factors that have nothing to do with hardiness. Grapefruit in general are more vigorous so probably spend more time than oranges growing. Even if hardiness while dormant would be superior, they may be anecdotically reported has more tender because is more probable to see one of them with frost damage due the longer time the plant spends growing? I'm doing a wild guess here, nut i also guess that a good rootstock may play an important role here.
Reading around however I got the impression the grapefruit can do better than orange in cold department.
However, in my city with temps going every several years and then around 14F, citrus are relatively rare (with the notable exception of the bitter orange). Oranges don't grow here, few plants have started to happear in last 4-5 years which have been exceptionally warm.
Recently I have found this plant that reminds me of a grapefruit. Seems seed grown, I haven't been able to inspect it, except from the road.



This isn't a 5 years old plant, and in 2011 we went to 12F.

The sometimes you get the unexplainable. I have a Tahiti lime that seems to have survived 24F; a small cutting, own roots, good place but nothing exceptional. Will keep an eye on it.

I'm not really sure how the thing will turn out. While theoretically oranges shouldn't grow here, given in fact the temperature you list, but a neighbor of mine has a orange tree planted in his garden since at least 5-6 years, and it managed to survive several freezes. I guess because our autumn last several months and plant acclimate pretty well? However, last winter the sweet orange plant survived this:



without even losing a leaf. And the plant wasn't even close to a building. I guess that the fact that it was a plant in a sheltered location covered from northern winds could have helped, but still. I'm not sure if that's just dumb luck from his side, but a this point i'm willing to experiment with several citrus and see if i can manage to grow some too.

I will attempt, next spring with a in-ground planting of Hirado Buntan and Oroblanco/Sweetie grafted on the same Flying Dragon rootstock.
I hope at least one of them will survive and to be able to show/clarify if any difference in hardiness exists among those plants.

Spring:


End of Summer:


Hopefully at least the hirado buntan should survive. I hope to be able to cover effectively the graft point even in the case of snow, that's why i grafted so low on the stem.

I guess an updated database backup copy doesn't exists? Because otherwise it could be relatively simple for me to bring all the forum back to life on a new server. There were a lot of informations there.

Wow very cool. If cattleianum in ground won't do, i think i'll go with this one!

Update, as requested. The graft was performed around 9th of September, and now i'm happy to confirm that something moves around the graft.
I have noticed a HUGE production of callus that is visible under the parafilm (hardly in this picture, but the green hue is callus):



Few days later (today) one of the scions (cleft graft) shows some growth:



I know that this is too early to say "it's done" but at this point i feel confident enough to say that the graft looks "technically" a success, and i'm going to assume than any further problem may be due to the lack of compatibility between the regular pomegranate and the dwarf one.
Now it remains to be seen if the dwarf rootstock will dwarf the pomegranate, but i don't see why it shouldn't.

Apparently this is one of the earliest cultivar, and following the reasoning that early cultivar need lesser total heat to ripen the fruits, i was thinking that maybe MAYBE i can give this a shot. I love dates, but regular dates sometimes ripen in southern italy but not here.
Problem is, finding a named date cultivar in europe is pretty hard! Where i can get one (hopefully TC) clone of this cultivar?

I have grafted a regular pomegranate on a dwarf clone (cleft and t-bud), hoping to get a smallish tree.



Has anyone ever attempted this? What should i expect?
So far the graft are still alive but is still very soon to say if they did take (they are just 2 weeks old).
I was looking for feedback and experiences.

Thank you for your follow up.
To be completely honest, I’m a bit envious. But I'll try to treasure your esperience if i'm going to ever graft Feijoa anymore.

Hey guys, i don't know if i did something wrong, or what but i can tell you for sure that my experiment did not brought any rooted scions to my collection: yep; they didn't root.

It was a badly executed lazy effort, but same procedure with lime and citron di produce take with 80% success rate so i'm going to assume that satsuma are, at very least way harder to root than lime and citron.