Author Topic: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F  (Read 7700 times)

tedburn

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The Chimera Prague lost the small fruit after a few weeks.

Two new plants for winterhardytest are new in ground.
First a multigraft on Flying Dragon with Morton Citrange, Dunstan and 5* Citrumelo.
Bloomsweet and Keraji are new grafts on the Flying Dragon.


Following picture is Ichangquat on Poncirus


tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #51 on: August 27, 2022, 01:50:19 AM »
Just a short update of my frosthardy citrus.
They all are doing well after 2 years in ground.
Though only Chimera Prague and Ichangensis Ivia had one flower each the others none. But all are good growing though some are slowly growing, especially my Thomasville and Ivia but also Chimera Prague is abmore slow grower.
Here two pictures of the smallest one, Thomasville, and the fastest grower Sanford Curafora F2 with an heigt now of 1,3 m, after restarting in may 2021 by 20 cm after frost damage in the 1. winter.
Enjoy your frosthardy citrus , ;D




tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #52 on: September 29, 2022, 12:57:56 AM »
In ground Ichangensis Ivia, slow growing, still get flower buds in early autumn.


tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #53 on: October 23, 2022, 02:36:15 PM »
After a long search still got some scions of Clemyuz 2-2 ( Ten degree tangerine), all took very good, also this one which I grafted directly on inground Poncirus. Interesting to see, how the first winter will get managed  ;)


raze

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #54 on: October 25, 2022, 08:06:06 PM »
Hi, just chiming in with my project of trying to grow outdoor yuzus in Helsinki/zone 6b.

- Started on March 2022 after ordering fresh yuzu for some seeds. Germination March-April.
- Moved small plants on my balcony during May for the summer. They seem to grow better indoors with lamps, but I'm low on space indoors.
- On October I decided to split plants into two groups. About a third I'm trying to make survive on my balcony during the winter. I'm planning to use various methods and see how they react to them. Some will be left fully exposured to the weather. Some will be stored on open and closed styrofoam containers. Some will be wrapped in frost-protecting blanket. Two thirds of the plants I brought indoors to grow some better roots & stem, and I will repeat the outdoor procedure next winter. Some of the plants I will plant outdoors next spring and see if they will survive at all in 6b zone.

The plants I'm trying to make survive the winter: https://imgur.com/a/g7wkLIE

Last winter Helsinki experienced temperatures going as low as -18c. My balcony stays about five degrees higher than this. Freezing temperatures lower than -25c are very rare in vicinity of the ocean, but occasionally do happen.

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #55 on: October 26, 2022, 12:24:29 AM »
Hello Raze, interesting and challenging project with nice plants  ;). Referring to my experiences, and reports of others, Yuzus can bear about -14 ° C in open ground.
So perhaps You also could use a heating cable for the cases when unfortunately some very cold frosty days will occur. In this way I could protect and save a Satsuma Collot in open ground in the very cold February 2021.
If you have fun with citrus you also could try Citrange or Citrumelo varieties or chimera Prag, which can take still a few ( 2-3 ° C) degrees more low temperature.
Best regards and good success.
Frank

Florian

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #56 on: October 26, 2022, 07:51:17 AM »
Hi, just chiming in with my project of trying to grow outdoor yuzus in Helsinki/zone 6b.

- Started on March 2022 after ordering fresh yuzu for some seeds. Germination March-April.
- Moved small plants on my balcony during May for the summer. They seem to grow better indoors with lamps, but I'm low on space indoors.
- On October I decided to split plants into two groups. About a third I'm trying to make survive on my balcony during the winter. I'm planning to use various methods and see how they react to them. Some will be left fully exposured to the weather. Some will be stored on open and closed styrofoam containers. Some will be wrapped in frost-protecting blanket. Two thirds of the plants I brought indoors to grow some better roots & stem, and I will repeat the outdoor procedure next winter. Some of the plants I will plant outdoors next spring and see if they will survive at all in 6b zone.

The plants I'm trying to make survive the winter: https://imgur.com/a/g7wkLIE

Last winter Helsinki experienced temperatures going as low as -18c. My balcony stays about five degrees higher than this. Freezing temperatures lower than -25c are very rare in vicinity of the ocean, but occasionally do happen.

Welcome to the forum and to the wonderful world of citrus.
Your seedlings look strong and healthy. However, you will have to be patient for them to flower (5-7+ years). If you plant them too small and they freeze back, you might never see flowers.

If you don't know it already, you should learn how to graft and sow some Poncirus rootstocks. It saves you so much time (and money too). As far as I know, there are no or few restrictions within the EU, so you should be able to source budwood from other growers fairly easily.

Poncirus trifoliata is the only citrus that could theoretically handle your zone without protection. Have a look at less awful selections like Poncirus+ or Swamp Lemon.

And finally, citrus coldhardiness depends on a lot of factors. They don't like too much winter sun followed by freezes or prolonged freezes. It doesn't matter that a Yuzu can take -12 C or lower. If your daytime highs stay below 0C for several days or even weeks, it will cark it much sooner.



tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #57 on: November 19, 2022, 09:45:59 AM »
My wife bought me very excellent Clementines, unfortunately there was no variety named. Due to a information from a french citrusfriend that clementine clemenules survived one winter with -14 ° C, I thought to try to graft the small twiggs which came with the clementines on some of my Poncirus and citrumelos in pots but I also made two grafts on my Sanford Curafora in ground. Not sure if this will work during winter but we' ll see in spring/ summer, if it worked. I thought it worth a try  ;).





vnomonee

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #58 on: November 19, 2022, 11:19:50 AM »
Those grafts can take even now, I've done them with 3 different mandarins and tangerines with stem from the grocery store fruit
around this time as well just make sure they are warm and have enough light. They will turn black or mold if they were not fresh enough
« Last Edit: November 19, 2022, 08:01:28 PM by vnomonee »

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #59 on: November 20, 2022, 03:22:35 AM »
Thank you, yes I put the most grafts in my greenhouse, only the two ones on Sanford stay outside by temperatures between 3 and 12 ° C the last and the following days - spring will tell 😅

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #60 on: November 30, 2022, 07:14:53 AM »
Some new candidates for winterhardiness test.
Depending on freeze depth and duration no or one or double layer frost cloth as protection in planning.
From left to right:
Meyer lemon seedlings, 1,5 years
ichangquat graft on PT, 1 year old
Ichangstar 60 seedlings in the middle
Star ruby seedlings, 1,5 year old on the right


mikkel

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #61 on: December 01, 2022, 10:43:36 AM »
Thomasville is a good story, Yuzuquat is an unlucky story.


Do you have a Yuzuquat?

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #62 on: December 01, 2022, 12:49:43 PM »
Hello Mikkel,
no sorry, there I made a wrong spell, this was an Ichangquat.
I have no Yuzuquat.

mikkel

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #63 on: December 01, 2022, 04:44:45 PM »
thank you!

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #64 on: December 10, 2022, 12:00:25 PM »
Winter preparations ready, longer lasting freezes down to -11° C / 12 ° F  announced, will be good hardiness test for some in summer or last year planted citrus, while last winter was mild.

Dunstan has to proof hardiness without protection


Ichangensis IVIA takes her 3. winter, only light stem protection.

two year old seedlings of Meyer lemon, Ichangstar 60, Meyer lemon and a graft of Ichangquat on Poncirus have ti proove their cold hardiness with light protection.
Goal is not to kill the plants but to select the hardiest for further cultivation.

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #65 on: December 20, 2022, 05:49:21 AM »
First cold spell (hopefully the only) this winter brought several frostdays down to - 8,6 °F / -12.9 ° C.
Interesting how microclimate differs by different places and passive protection.

Here the coldest place
[/url]


Only 3 m distance but in protection of a short wall brings 2 ° C of higher temperature



the 2 year old seedlings, see last post, with backwall greenhouse and front protection airbubblefleece shows
a gain of about 4° C




last (warmest) place and double protection with fleece and air bubble fleece shows a gain of nearly 7 ° C of cold reduction.
On second picture are the protected plants, one and two year old graftings of slava micurina, Duncan grapefruit and Bloomsweet graft.




Conclusion, for shorter periods passive protecton can be very helpfull against frost damage, also protected places in the garden.



bussone

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #66 on: December 20, 2022, 10:30:51 AM »
First cold spell (hopefully the only) this winter brought several frostdays down to - 8,6 °F / -12.9 ° C.

Quick fix:
-12.9 °C is +8.6 °F.

-8.6 °F would be -22.6 °C.

Poncirus can survive that, but you probably need a windbreak for it. With some luck, they've been found on the 5b/6a border.

kumin

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #67 on: December 20, 2022, 10:59:57 AM »

[




A few F² Citranges survived -11,8 F ( -24,5 C) in January 2019.



tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #68 on: December 20, 2022, 11:14:43 AM »
First cold spell (hopefully the only) this winter brought several frostdays down to - 8,6 °F / -12.9 ° C.

Quick fix:
-12.9 °C is +8.6 °F.

-8.6 °F would be -22.6 °C.

Poncirus can survive that, but you probably need a windbreak for it. With some luck, they've been found on the 5b/6a border.

Yes Bussone, your are fully right, temperature was +8,6 F, my head was perhaps already to early at the ° C

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #69 on: December 20, 2022, 11:25:01 AM »

[




A few F² Citranges survived -11,8 F ( -24,5 C) in January 2019.



Kumin, you did really a extraordinary breeding and selection, not sure if Poncirus is really much hardier. Only a pity, that frosthardiness and edibility are still in a big distance and will need a lot of further time and work. To my knowledge the only citrus with excellent  fruit when ripe and really frosthardy citrus is Thomasville Citrangequat with hardiness about - 15 ° C but still one problem is that fruit ripens in spring and will be spoilt in winter freeze under -5 ° C.

kumin

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #70 on: December 20, 2022, 12:05:07 PM »

[




A few F² Citranges survived -11,8 F ( -24,5 C) in January 2019.



Kumin, you did really a extraordinary breeding and selection, not sure if Poncirus is really much hardier. Only a pity, that frosthardiness and edibility are still in a big distance and will need a lot of further time and work. To my knowledge the only citrus with excellent  fruit when ripe and really frosthardy citrus is Thomasville Citrangequat with hardiness about - 15 ° C but still one problem is that fruit ripens in spring and will be spoilt in winter freeze under -5 ° C.
Tedburn, good point regarding early fruit maturity. Deciduous foliage is also quite important. I see a goal of breeding for Citrus fruit approaching the quality of conventional cultivars on a tree similar to Poncirus, minus the thorns.
Several of my selections approach, but don't quite equal the hardiness of Poncirus. Only one has fruited and while the juice is acceptable as a drink, the flavors are too intense for fresh eating.

Ilya11

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #71 on: December 20, 2022, 02:01:01 PM »
Tedburn,
I have not measured temperatures in different places of my garden, only one sensor rather close to the house. Minus 8C one night, three days without ground defrost.
None of my unprotected citruses including three oranges grafted on high stem of PT show damage for the moment.
Best regards,
                       Ilya

bussone

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #72 on: December 20, 2022, 02:09:23 PM »
Kumin, you did really a extraordinary breeding and selection, not sure if Poncirus is really much hardier. Only a pity, that frosthardiness and edibility are still in a big distance and will need a lot of further time and work. To my knowledge the only citrus with excellent  fruit when ripe and really frosthardy citrus is Thomasville Citrangequat with hardiness about - 15 ° C but still one problem is that fruit ripens in spring and will be spoilt in winter freeze under -5 ° C.
Tedburn, good point regarding early fruit maturity. Deciduous foliage is also quite important. I see a goal of breeding for Citrus fruit approaching the quality of conventional cultivars on a tree similar to Poncirus, minus the thorns.
Several of my selections approach, but don't quite equal the hardiness of Poncirus. Only one has fruited and while the juice is acceptable as a drink, the flavors are too intense for fresh eating.

Interesting to observe that zanthoxylum, one of the few Rue genera that is hardier than poncirus, is also deciduous.

tedburn

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Re: Frosthardiness experience with citrusvarieties in zone 7, down to 3,2 F
« Reply #73 on: February 04, 2023, 01:59:23 PM »
Today made a check at my 5 graft Flying dragon. After a low of 8,6 F and passive protection also the new grafts of summer 2022, Clemyuz 2-2 ( ten degree tangerine),Bloomsweet and Poncirus #7 look very good with small green buds. Morton and 5* Citrumelo grafts of 2021 also look nice and healthy.
Also Ichanggqat, plant on the left side,
in ground since  spring 2022 looks good.



 

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