Best sweet peppers for colder northern climates?

[Justin Jardinier]

I'm interested in breeding sweet peppers for outdoor growing in the UK. My final wish is to cross various species, including annuum, chinense, and baccatum heading towards hoping to increase chances of crossing with flexuosum, thining interspecial crosses might give more chance of being able to cross with flexuosum. So I'm curious which varieties of these will be the best starting point.

For chinense and baccatum, the choice of sweet varieties is limited, and I'm guessing none of them are particularly suited to this climate, but it would be nice to bring in some of their genetics and flavours. But for annuum the choices are many. So I would love info on which may be best to use.

The ones I am so far growing with the highest hopes are:
- Orange Lesya
- Purple Beauty
- Healthy Pepper
- King of the North

I also recently heard about Северное сияние (Northern Lights), that it apparently withstands frosts up to -2C. Does anyone know how this variety compares with those 4 I just mentioned? If it would grow noticeably better than those here, I should perhaps focus on that instead. And, any tips on other nice tasting suitable varieties would be appreciated!

And, since tetraploids seem to be better in colder climates, has anyone created or worked with any tetraploid sweet peppers? That could be a great avenue to pursue. Any tips on how we can induce tetraploidy without having a lab, would be appreciated! Is there a how-to guide like, for using colchicine ...? There is a paper that might explain - 'Establishment of tetraploid plants of Capsicum annuum L. by colchicine treatment with the analysis of flow cytometry' by K. Ishikawa et al., but I can't access it.

There's also this article on using oryzalin to induce polyploidy: gardenscientist.wordpress.com/2013/09/09/inducing-polyploids/
But I would be especially interested to hear from anyone who has had success, with any method.

[Steph S]

It's been a while since I grew peppers, but really enjoyed the flavor of some heirlooms especially the frying type peppers, like Jimmy Nardello.
Jimmy was productive and pretty tolerant of conditions here.
Frank's was probably the best in terms of a pointy bell type pepper. Early.
Petit Marseillais is an orange one with pretty thin walls but very good taste, crispy, multi-use.
The thicker walled peppers, like Pimento, were a bit slower and less productive but delicious.
I didn't find earliness or great yields from any of the larger pepper types like Corno di Toro.
I grew a lot of mild hot peppers too.  All annuum for the most part and they were decently early and tolerant of conditions.
Pepper PLANTS will tolerate temps down to freezing without blinking, unlike tomatoes.  OTOH they will be very unhappy if their roots are cold for weeks at a time.   
The real question is getting conditions where they're happy to fruit.  They have a narrower 'goldilocks' range for pepper setting, with nominal optimum day/night 20/18C.  Of course they do set outside that range too.  If the roots can be kept warm, they're really adaptive and tolerant of air temperatures.

[Justin Jardinier]

The real question is getting conditions where they're happy to fruit.

Ah yes, this is an excellent point! I'm guessing that the Russian one I mentioned above might be good in that regard, or hoping so anyway. But yes, that is the key really isn't it. Though also would be cool if some varieties, maybe some Russian ones, can tolerate colder ground too. Hmm, that has me thinking, I wonder if anyone has used flexuosum rootstock? Maybe not necessary since we need the warmth anyway for fruiting, but, I wonder if one of those cold tolerant Russian ones, grafted to flexuosum rootstock, could become perennial in some not-too-cold places?

Jimmy Nardello's on my wish list, thanks for affirming that! I have Petit Marseillais. It didn't flower as early as the others I mentioned but I'll try crossing with it too.

I didn't find earliness or great yields from any of the larger pepper types like Corno di Toro.

I'm wondering if this is a thing with peppers and tomatoes, that 'earliness power' and 'bigness power' are two independent variables that work against each other. If so, it might be worth crossing big annuums with the smaller sweets from other species anyway, if the resultant size reduction from the cross 'reveals' more earliness, or, like gives a cross which is similarly early to others but medium sized instead of small? Just speculating here.... but it makes me consider not leaving out large ones entirely from a breeding program. Similarly I'm trying to include some fat tomatoes that aren't as early and some salad sized ones, in making interspecific crosses, hoping to get early enough but more reasonable sized hybrids.

[Steph S]

Yeah, don't leave out the big ones!  The heirlooms may not be early, doesn't mean you can't breed some earlier biggies.  This has been true with tomatoes, so why not peppers.
I think it's true that peppers like some heat to ripen, but that is probably genetically variable too.

I did have a Russian pepper among the ones I tried in ground, the year of a great pepper failure!  It was especially cold, and they really produced nothing, including the Russ, whose name is now forgotten.  Cast a wide net, try as many promising vars as you can lay hands on, is always a good bet.  Some will get written off while others become favorites and breeding material, and always room to squeeze in a few new ones to try every year... that is until your own breeding experiments take off, and eat up all the available space. 

Cold tolerant rootstock is a really interesting idea.
There are techniques that work as well, to keep your roots warmer:  raised rows; black mulch. Or growing above ground in black pots.   
The way the weather is going, you'll be looking for heat tolerance as well...

[Justin Jardinier]

I did have a Russian pepper among the ones I tried in ground, the year of a great pepper failure!  It was especially cold, and they really produced nothing, including the Russ, whose name is now forgotten. 

Ah that's a shame.

Cast a wide net, try as many promising vars as you can lay hands on, is always a good bet.

Yeah, though it would help a great deal to start with ones known to perform very well. I have been trying already this year but thought now I should ask around a bit more :-) Casting a wide net is nice but growing out F2 for even one cross will take lots of space, and since I have 3 sweet chinese varieties to cross to annuums and to 3 baccatums, and will then need to cross baccatum x chinese to annuum, and cross annuum chinese to baccatum, it could get out of hand very very easily! This season I'm keeping my plants very small, and was assuming these crosses are hard to make anyway, so my wide net as it is, is largely just to increase chances of any succesful crosses.

If anyone is in the UK and wants to collaborate, that could help this space issue a lot! I already have so many interspecial tomato crosses made this year to grow out!

[Tim DH]

Outdoor UK pepper growing is a fine idea. ... I struggle to get a worthwhile crop even in the greenhouse!

I've half a mind to trial some pepper grafting next year, to see if that improves my greenhouse crop.

Tim DH

[Diane Whitehead]

I grow mine in black plastic pots, outside until we get frost, which might be in October.  Then I put them in my unheated but frost-free greenhouse.

The only one that has ripened so far this year is an unnamed annuum from a friend.

The following have unripe peppers, all annuums:

Ashe County Pimento, Corbaci, Jimmy Nardello, Etiuda, Lipstick, Nadapeno and Right on Red.

The rest have flowers but no peppers yet.

[Ferdzy]

For pure earliness, nothing beats Bacskai Feher. I also have to say we are having a very poor year for peppers, and thus far it's the only one churning (anything) out.

[Garrett Schantz]

Capsicum annum:


'Alpine Poblano' Pepper

'Holy Italian' Sweet Pepper

'Mountain Roaster' Sweet Pepper

'Gatherer's Gold Sweet Italian' Pepper

Dwarf Tepin Pepper (Dwarf Gene)

Cañoncito Field 7 Landrace Hot Pepper (Precocious Flowering)

Doe Hill (Dwarfing Gene)


Capsicum chinese:

CGN 20800 (Grows in mountains which experience some cold and frost)

Dwarf Aji Charapita (Dwarf Gene, maybe different from Annum's Gene)

Yaki Blue Fawn (Filius Blue
Annum, crossed into a Chilense)



Capsicum baccatum:

'Aji de Colorado Alpino' Hot Pepper

Sugar Rush Stripey (Simply interesting due to the fact that it's fruits, not its leaves are variegated - different form of variegation found in other species. And it shows up on ripe fruit.)



Capsicum Praetermissum:

CAP 1141




Tubocapsicum Anomalum, is pretty interesting. There's different subspecies from different islands. These can handle frosts. Not a Capsicum, but it seems to be a sister genera.


Capsicum flexuosun - it has different "races" like S. habrochaites for example, has.





I'm hoping to grow some of these out, finally next year.


I had issues before. Timing, not enough room to grow things indoors.



Some or many of these, are from a single breeder group, they grow things in mountain regions - they tend to select for cold or frost resistant plants.


Sugar Rush Stripey, isn't as productive as Aji de Colorado Alpino. Nor as cold tolerant and the like.


But, it's probably worth crossing into Sugar Rush Peach Stripey, just to introduce the variegated gene.

The fruits are highly ornamental while still being tasty.



I added in some of these fun ones, because you mentioned wanting to breed with different species.

I'd work on finding different cold or frost resistant accessions of species and things, and creating larger fruited / tasty varieties before trying out interspecific hybrids.



And, any traits which aren't found in other species, I'd play with those in the meantime.


Dwarfing genes, don't work too well in larger varieties, larger fruited ones.


But, plants grow out shorter and bushier. Mix that with earlier flowering traits, and the fact that the Dwarfing also seems to cause earlier flowering and things itself.

You'll likely end up something even earlier.


The Dwarf Chinese, seems to grow somewhat differently than Dwarf Annums. And it grows out bushier and seems to have a max height, not as small as Dwarf Annums.


If they have different Dwarfing genes, mixing them may be fun.

Though, a super small earlier Pepper may not do well on production.




Cañoncito, has a precocious flowering trait - most peppers have a similar trait. Those ones will flower from stress or from being grown in small pots. A lot of wild peppers will grow on rocks or areas with small amounts of soil, and attempt to grow there.

So, those cases are usually flowering from stress.

Cañoncito, seems to just flower, whenever it wants.





I moved to Mississippi, so this breeding isn't as high up on my list of things to do anymore.

But, it's still on some lists because it'll extend a lot of seasons.


C. flexuosum, is actually largely interfertile with both C. chinense and C. annum and used as a bridge for both species.


The main issue, seems to be that it's hardiness is caused by multiple traits which work together.


Offspring in crosses, aren't as hardy unless there's backcrosses.

Plus some hardy genes are carried by the male and female parts of C. flexuosum.


So, it frankly ends up being a lot of breeding work.


Rezha Macedonian, has a crunch to it - due to a tapering gene which also creates thicker walls by proxy. Or corking.


Not all Pepper species backcross very well.


The ones that do, can end up crossing or being fertilized by multiple species.


And peppers are more or less promiscuous. So, selecting offspring for certain traits usually means you'll need to cull a lot of plants.


Their flowers are a pain to bag. They'll suffer from inbreeding depression in a lot of cases as well, if they're forced to breed together in small lines too much.


Flexuosum breeders also have to select for larger fruits.



Tomatoes don't seem to care as much about inbreeeding depression.


Crossing some species together, does reduce some inbreeding depression issues.


Yaki Blue Fawn, is blue - it has anthocyanin. Plus it's highly disease resistant and cold resistant. Plus it's pretty productive.

It's not a sweet Pepper, but it's likely to cross over easily to C. annum or chinense.



Hopefully, some of this helps.

[Garrett Schantz]

Some seeds mentioned here are hard to get.

You'd have to check HRseeds or other sellers shipping conditions and things to see if they ship to certain areas or can do so with phytosanitary certificates.

Fatali seeds usually sells some of these things in the UK if I remember correctly.


I have some friends in finland who grow their peppers and see their stuff sold in markets.

[Justin Jardinier]

The only one that has ripened so far this year is an unnamed annuum from a friend.

The following have unripe peppers, all annuums:

Ashe County Pimento, Corbaci, Jimmy Nardello, Etiuda, Lipstick, Nadapeno and Right on Red.

Ah, that's a shame about Jimmy Nardello, I heard great things about it and was wondering how it might do in a climate such as the UK. Where are you? The unnamed one sounds interesting! Is it a pointy pepper?

I was focusing on earliness in my search and thinking the Russian varieties might be among the best, but after having a chat with someone it seems the key is adaptation to the cooler Summers, whereas in Russian they can have hotter Summers.

Garrett this might also rule out wildmountainseed.com's peppers, which interested me until I realised this. Maybe they also would not work for that reason.

For pure earliness, nothing beats Bacskai Feher.

Has anyone tried that in cooler cloudier climates, like the UK for example?

Capsicum annum:

Thanks for this list Garrett. I looked some of them up but aside from the ones from wildmountainseed.com they seem to be hot peppers, not sweet peppers. Are any of them sweet peppers that are adapted to cooler Summers?

C. flexuosum, is actually largely interfertile with both C. chinense and C. annum and used as a bridge for both species.

Not sure if I understand what you're saying here. It's used to bridge chinense and annuum? So far as I understand, annuum x chinense is possible directly, though crossing annuum with baccattum requires a chinense bridge. So I don't understand why one would need to use flex as a bridge. Also while I have read of flex crosses in one academic paper ('Reproductive Compatibility in Capsicum is not Reflected in Genetic or Phenotypic Similarity Between Species Complexes'), I have never heard of any 'civilian' who has ever successfully crossed flexuosum with any domesticated species. Do you know anyone who has successfully crossed it with chinense or annuum?

Flex. is the only hot pepper I am considering because of its potential to make perennial peppers for a cooler climate, which could be great generally but also specifically for giving a decent head start to the season. If I could make crosses, I would plan to breed out the heat.It only seems worth doing that because of the extraordinary cold tolerance.

The main issue, seems to be that it's hardiness is caused by multiple traits which work together.

Offspring in crosses, aren't as hardy unless there's backcrosses.

Plus some hardy genes are carried by the male and female parts of C. flexuosum.

Do you have references for that? I'd be interested to read them. Makes sense that it would be hard work... And do you know how to access any such crosses? If there's a cross out there of flexuosum with a sweet domestic pepper, I would be very interested indeed! I even wrote to one of the authors of that only paper I found that detailed making successful crosses with flexuosum,  but got no reply. Here's a quote from that paper:

No hybrids were achieved with C. flexuosum or C. minutifolium as female parents, however C. flexuosum hybridized as the male parent with C. chacoense, C. annuum var. glabriusculum, C. baccatum, C. tovarii, C. annuum and C. frutescens,

Plus some hardy genes are carried by the male and female parts of C. flexuosum.

Interesting. I was planning to make some mentor grafts, and that could be a way of getting some of the female elements even without making any crosses. Though if it's merely cold tolerance and not earliness or adaptation to lower Summer temperatures, cold hardiness by itself would only prove valuable if it can go far enough to cross that threshold of surviving the whole Winter. Though even if surviving in a greenhouse over Winter, that, while not being my aim, could prove valuable to greenhouse growers.

Flexuosum breeders also have to select for larger fruits.

Do you know anyone doing that? And if any seeds might be available for larger fruits flex varieties? Also different accessions have varying cold tolerance - if there are ones with the greater cold tolerance (apparently some of those in Brazil), or ones with less heat (apparently Paraguay), that have been bred for larger fruits, that would be most interesting.

[Justin Jardinier]

Oh and I forgot to mention, the person I was chatting with who recommended against Russian varieties due to needing hot Summers, even King of the North not doing well (which was disappointing), had this recommendation:
All the eastern European fat pointy types such as:

Kapia
Amanda
Slovakia
Nova
Amy
Napia

And Kaibi from Real Seeds:
https://www.realseeds.co.uk/sweetpeppers.html

[Diane Whitehead]

Where are you? The unnamed one sounds interesting!

My locality is at the bottom of every message I post.  Victoria is on the southern tip of Vancouver Island, on the Pacific coast of Canada.  Before garden books were written for our conditions, we used to use English garden books but we are not really like England.  You get rain in the summer, and we don't, so we have to water frequently.

I can send you seeds of the unnamed one.

[Mica Winnower]

Diane has essentially the same climate as I do, which is not like the climate I'm used to growing up in the eastern half of the country. The lack of inter-seasonal rain, thunderstorms, and how quickly things turn dark and damp have really not done much to improve my opinion of the PNW's climate. That, and I really, really miss seeing oaks as a player on the landscape. 

None of my peppers did well this season, as mild a season as it was.
I've gotten a few green shishitos, and my Corno di toro has made 3 peppers that are finally mostly red.

I might save seed from the corno di toro, since it's the only one who did well for me. My King of the North got sun-scald on the only pepper it produced. Puny little plant didn't even break two feet tall.

[Justin Jardinier]

Has anyone here grown Fresh Bites pepper in a colder area? I only grew 2 pepper plants outside, King of the North, and Fresh Bites. I was really surprised that Fresh Bites, which I thought is quite late so should in theory do badly here, gave ripe fruits and is still alive and ripening more now after the temperature going down to 0°C (32F) on the 16th; whereas King of the North's fruits never ripened and now the plant is dead from the cold.

Here's a pic of Fresh Bites from the net for reference - it's really tasty!