The Tropical Fruit Forum

 I have tasted Batumi Citrumelo, Dunstan, Swingle 5 Star and a mislabeled Citrumelo with a high rate of zygotic seedlings.
--> Batumi is hardly bitter and has no Poncirus off-flavours. It is sour but very tasty.
--> My Dunstan is as discribed here. Like a good grapefruit only sour. It contains a sticky substance. But the substance is tasteless.
--> Swingle 5 Star is quite bitter, too bitter for me. It has also strong Poncirus off-flavours. For me not edible. But I am willing to believe that it is as good as Ilya describes it in warmer climate.
--> The mislabeled Citrumelo may be Yuma Citrange = Sacaton. This would at least explain the misspelled and strange name the nursery gave to it ("Yuma Gwangne..." from handwritten "Yuma Citrange"?). It is very aromatic and juicy but also bitter with Poncirus off-flavours. Sourness is moderate. I would say: High potential for breeding but almost inedible as it is.

Swingle 5 Star is not hardy in my climate. It is killed to the ground even in mild winters with lows of only -10°C / 14°F. Ilya states a much better frost resistance. But the growing period at my home seems to be too short for better performance. I have not tested the other citrumelos. Seedlings of the mislabeled Citrumelo were all killed to the ground at around -8°C / 17,6°F, except two zygotic ones that only lost their leaves.

Regarding hardiness of Poncirus and Citrumelos, I remember a scientific article that stated a hardiness for Poncirus between -14°C (6,8°F) and -20°C (-4°F) depending on the cultivar. Other sources attributed a hardiness of about -25°C (-13°F) to Poncirus. So the genus Poncirus consists of  different gene lines with different hardiness. I can confirm from own experience that some Poncirus seedlings are hardier than others.

The main challage for Poncirus in my climate (cool atlantic climate) is late frost in spring. It cannot handle late frost in spring (for instance -8°C / 17,6°F at the end of April) very well as a plant adapted to continental climate. In one year, Poncirus was severely frostbidden while Yuzu had no damage at all. (In the next year Yuzu was dead and Poncirus alive.) With this in mind, I can image that a citrumelo is at times hardier than pure Poncirus. a) Hardier when compared to a Poncirus with low hardiness. b) Hardier under late frost when slower to grow in spring. c) Perhaps also hardier when it grows faster than Poncirus so that it hardens off more quickly in autumn.

But usually Poncirus should be much more frost resistant than any of the known citrumelos.

Florian, the pictures show Citrumelo 82?

My Dunstan did not do very well the last two years because of earth problem as I later realized. It is on Swingle Citrumelo. It had no root rod but no real root growth either. Seems to be much better now after repotting.
The plant stood in a pot in the wintergarden under glas. But I placed it outside from about mid Mai to October. Fruit was not very big (about the size of a Clementine) but almost totally yellow in autumn. That the plant stood under glas in spring allowed it to be more than a month faster than plants overwintering outside. I forgot when it bloomed. But it was probably in March not in May as Poncirus grown outside does.

Good to read about your experience with Citrumelo 82, Florian.

My Dunstan Citrumelo has a very good aroma and NO Poncirus off-flavours. It is just like a sour grapefruit with some sticky substance in the fruits. The sticky substance is tasteless.

The fruits of Swingle 5 Star that I have tasted were very bitter. I prefer by far my Dunstan and my Morton. Batumi Citrumelo is also very good, maybe the best. Batumi is too sour for eating out of hand. But my Morton was sweet enough that I ade some fruits fresh as they were. I found their Poncirus flavours quite tolerable.

Thank you for the replies. Hmm, so not easy. Springtimes makes creative and my shopping addiction has become awake again. I have to think about getting the plant. Or should I better focus on my own hybrids, especially on my Ichang Papeda x Moro hybrid? Space is so limited... Maybe I shall wait with new plants.

Does anybody know which kind of seeds C. ichangensis x C. sinensis from Bernhard has?

As far as I remember there is also an analogous seedy cross from elsewhere around. Does anybody know which seeds that has, zygotic or not?

Thank you for your pictures, Kulasa! They clearly show where the shot comes from.

Inspiring. I shall begin producing leave cuttings, also.

Poncirus in general is scentless. But there are at least 2 clones in the world with very flagrant flowers. One is known to Mikkel. The other one was found by myself. I found an article of a woman in the internet that praised her Poncirus for its beautifully flagrant flowers, obviously not knowing that Poncirus is usually not flagrant. I wrote her an email and finally got budwood. I was NOT able to test her claims because I do not have flowers yet. But she was very sure about the strong smell of the flowers. There are no indications that she has a Poncirus hybrid. Seems to be pure Poncirus. Ilya got budwood from me. Ilya have the grafts flowered since then?

Most nurseries that claim they have a flagrant Poncirus simple lie. That is at least what I believe. If they were true many people had a Poncirus with smelling flowers. But fact is that hardly any knew one when the question was first rised in this forum. Many nurseries even present pictures of normal lemons when they sell Poncirus. And then they speak about flagrant flowers because they believe that any Citrus plant has flowers with scent.

What exactly do you mean by "Red Lime"? Is it the cross with Fingerlime described here: https://en.wikipedia.org/wiki/Blood_lime? Or is it another plant?

A cross of Citrumelo x Changsha Citrandarin would have the advantage that frost hardiness is very likely. A good hardiness cannot be garantied but since you have 2 Poncirus grandparents involved and one hardy mandarine it is very probable that seedlings can at least take -15°C / 5°F. And since two of the grandparents are sweet (Grapefruit and Changsha) there is some hope that the hybrids will also bear sweet fruits.

The toll regulations are as often a great problem. We have in Europe a fully hardy Changsha Citrandarin (US 899 F2 from "Usirius") with zygotic seeds and we have a kind of sweet Poncirus (Poncirus Kinga) with full hardiness which is actually also a hybrid. The former has fruits with medium acidity (sour but less than Poncirus), good mandarin aroma and mild Poncirus flavour. The latter one is said to be sweet and to resemble Poncirus in other regards.

Perhaps yopu have similar types in the States.

Mkono, go ahead and be optimistic! Great project. You will have enough survivors when you start with such a great number of zygotic seedlings. And you will probably have some good tasting seedling at the end.

Dr. Frey sowed 200 seedlings from Sanford Citrange (a zygotic variety). He falsely killed all trifoliate seedlings and still ended up with two edible varieties, Sanford Curafora and Vanessa. Ok, they were only moderately hardy. But from what a small number of seedlings!

Lemon and Citron should be distinguished, right? Lemon is a hybrid between Citron (male part) and Sour orange.

Tedburn,
we will see. You may be right. Both parents are late. Staraji fruits are now still green and quite small. Trifeola is not extremly late but too late to be harversted in the year of flowering. I do not know how the genes will be mixed. I could imagine that offspring is early maturing. Most Poncirus hybrids are quite early (though not early enough). So if the Poncirus influence dominates I will have early fruits. That is admittingly only to a certain degree probable and far from certain. Both parents have at least the genes for sweetness. And zygotic seeds are also possible for my cross. Keraji has edible peel so Staraji has at least the genes for edible peel.

I have never eaten a Staraji fruit. My plant bloomed for the first time last year. I only have Ilya's description which says sweet and without off-flavours. That was argument enough for me to try the cross.

By the way, most of my Citrumelo seedlings (Sacaton??) were serverly frostbidden even under the snow at about -8°C / 17,6°F. But some zygotic ones did not even suffer leaf damage. Lets hope that my Trifeola seedlings will be among the surviving ones the next winter. Its a lottery but with a realistic chance to win.