I am planning to put several more varieties inground next year and wanted to ask about several that I have, to see if anyone has any experience with them here in the North in ground. I am in SW PA, zone 6a. Growing season is not long enough for some of the later varieties inground, I believe. I will be cutting them back and covering them in winter. 

So far I have only overwintered one plant one winter, a Sal's (Gene or EL), which was very successful.  Basically pruned the plant to 2.5 ft tall, surrounded the plant with a wire cage 5 ft tall, buried the lower 1 foot with large chunk pine bark, surrounded the rest of the plant with bags of leaves, covered with tarp, with rodent poison inside and outside the cage.   Based on that success I put 6 more inground late spring this year,  - 2 MBvs, Chicago Hardy, Bryant Dark, Adriatic (JH), Salem White.  I have several more proven varieties to plant next year including Florea, Brooklyn White and several other Mt Etnas.  Last winter in my location we had a low temp of minus 4 one night, but rest of winter did not get below 5 degrees, I think.

Anyone in the North have experience with winter survival and productivity of the following varieties in ground?
Atreano or Atreano Gold?
Negretta (or Jason's Unknown Black Ischia)
Nero 600m
Valle Negra
RdB
O'Rourke
Niagara Black (or LdA)
LSU Tiger
Chiappetta

Thanks for any responses

ed,what about letizia it is way better than chicago hardy in growth and production ,i will show you when you stop in ,letizia is my favorite in ground ,i haven't had any better yet ,

I swear I do not get how "they" decide on hardiness zones.  Chicago is now Zone 6b too, but we had -20 F more than once last year.  Granted that was the wind chill, but it routinely stays at or below 0 for long stretches.  I'm scared to death to put my plants in the ground because I don't want to lose the top growth.  I really do wish you the best of luck with the in-grounds.  If I ever get the nerve to put one in the ground I'll copy your method for winter protection.

Hi Ed. Gene Hosey said Negretta was his hardiest variety.

I have tried most of your list in ground here, although only a couple years for most, and some like Atreano were planted in a poor location (where all other varieties are unproductive) so it invalidated the results. Valle Negra is affected badly by FMV, Chiapetta is planted in a frost pocket, an unknown I think is Tiger seems to have individual tree issues or something, not much growth and no fruit, but that is not typical for the variety.

LdA has been ripening for 10 days after top kill last winter. Nero 600 m is close behind. RdB sets figs late, or not at all, after top kill or hard pruning.

Hi Ed
Smart to plan! 
Nice to see people growing their in figs in ground undoubtedly best for eating and long term easiest way to grow figs in our zone.

Comment; Foz zone 6a Adriatic JH will be very late to ripen in ground and figs tasteless contrary to how super delicious they are in containers.

One gap I see is that you don't have any early light figs in your in ground collection. 
I have been growing Fico Bianco, Lattarola and Dalmatie.  3 very different delicious figs and they have come through every year with big production for me.

I already sounded the Allarm ,in some other posts,about some certain varieties ,that will not form fruits in the Spring if soil is cold ,because of a cold period late in the Spring.
Tho some of my fig trees came out with live wood,they grew very strong but form very few fruits.
I suspect the root temperature need to be at about 60 F in order for fig to bolt out(fruit).
I suspect Mount Etna type,and ,Improved Celeste, Adriatic JH, Atreano,will form fruit when Root temp,is 50 F or less.
I agree with above poster that Adriatic JH will make more delicious fruits ,in zone 6 and 7,if in pot.
I agree Ronde de Bordeaux,Negretta, Kathleen Black,Maltese Falcon,will not fruit much if in ground ,when roots are cold, tho they are  early fig.
From late figs,only Italian 258,produced a good crop,all other choice cultivars,like Nero 600 m,Vasilika Syka, Col de Dame,Longu D'Aout,Sicilian black,Dalmatie, Noire de Caromb,only produced a dozen fruits or less,and  i am not sure they will all get ripe.
One other reason,i suspect,is that my late ripening figs,are old now,over 5 years old,and they developed deep tap roots ,additional to side roots,and so,they remain cooler much longer ,and also they suck more water than they need ,having tap roots,and so they grow very strong,very fast,but do not fruit properly.
That is because ,in Western Asia where fig originate,the soil is dry deep in the ground so roots can't suck this much water as they can here  on the east coast.
As usual no one know everything so we learn as we grow them, sometimes from mistakes.!
So my opinion,is keep late ripening varieties in pots,like 10 gal. is ok,and grow in ground only early varieties i mentioned above ,and other you might have.
I plan to dig out my late ripening varieties,or figs that did not fruit well this year,and after a hard pruning plant them in pot.
I know it is a problem with storing them,but where there is a will there is a way.
The last resort is ,I will bury the pots and ,take them out is the Spring,if i can't find room in my garage
I hope this will help

Edit note:If you live on the southern side of a hill,with a  10 degree inclination or more,then grow all figs in ground and protect best you can,because they will produce incipient fruits early,and the water will drain down the hill,and not affect figs.
My observations are valid for people growing plants on a flat garden,in our climate in NJ and Atlantic states.

Sorry for the slow response, I was away.

Here in RI (Z6B, min winter temp ~ -5F), I've had RdB inground through two winters.  After late fall pruning and with good winter protection, I've had essentially zero loss of branches on it.  The plant has produced well, ripening on the early side (starting late August).  For comparison, Florea has seemed similarly hardy but begins to give ripe figs roughly a week earlier -- mid August.  Mt Etnas (HC, MBvs) have seemed slightly less hardy, with maybe 30% loss on HC and 10% on MBvs; these varieties begin to give ripe figs roughly a week after RdB -- very late August / early Sept.  FWIW, I THINK that the HC was a little more aggressive coming out of dormancy and got zapped this year by some unseasonably cold weather.  

Re Pino's comment, my best tasting in-ground fig is the late variety Gene's Paradiso.  With pinching and great micro-climate, it ripens here from late Sept into early November.  It has been fairly hardy, maybe 10-20% damage on average over three winters.  So it may be borderline for Z6a. 

Herman --

Thanks for the comments.  As mentioned, I've had good success with RdB outside.   My site faces WSW and gets good sun, midmorning to sunset; it's a hill so excess water can run off; and there are big rock walls on the hill immediately behind the plants that hold heat.  So all these factors may help.

A question based on your observations:  Am I'm right inferring that dark (e.g., black plastic) mulch, warming the ground in spring, would encourage more / earlier fig production?

The range of experience with some plants is interesting. I like the black plastic idea, maybe black weed barrier cloth would work too?

Pino, I do have a Lattarula and a 2nd yr Stella( which looks same as your Dalmatie) that I was thinking of adding inground and planning a Brooklyn White that is a small first year plant at the moment. So I will have some light figs in the earth, but I honestly like dark figs better.

Of course Black plastic will help on ground and also ,Black pots will help,and i did buy 8 black pots 17 gal each,but of course i do not have to fill them to top,only what plant needs depending how big root ball.

It's very interesting reading you in ground trials even if I will never planting ground in my zone. It's good to know about the 60° roots, I had heard that fruits won't ripen at least than 50° before. Have you found it to be the case that figs ripen faster in pots than in ground? If so is the change in timing simply the cold ground?assuming constant water so no water stress in pot or ground, does the added sun temp on pot make such a great difference?

Yes late ripening fig trees, get ripe in pots earlier than in the ground in cold climate,like zone 5 ,6 ,and 7.
It is a fact. But it takes more work,and a good shelter in the Winter.
In hot dry climates it is better in ground.

Hi eboone,
Always good to have a backup tree for the ones you try in ground. Just in case.
Your Zone6 is pretty similar to my Zone7 ... LOL ...

Your trees in ground will benefit a lot from some protections. Here are mine :
Plant an hedge all around your garden. Keep the trees in the hedge at an height of 3'/1m . That is enough to cut the wind blow.
Those trees will act as a water draining facility. It might be a small pain in the summer as you'll have to water a bit more, but definitively it will help drying the dirt in the Winter.
In the hedge, I use trees that are easy to propagate like elderberry and forsythia and some  I bought like a peartree .
It is my belief that one should not lay plastic on the ground as this is a magnet for rodents to run under.
Instead use loam. Loam is dark and will (IMO) help keep the feet of the trees a bit more warm. Cover with loam a squared zone of at least (2' * 2') (60cm*60cm) around each figtree. Thickness of the layer : 10cm/3'' .
I suppose that you already know my 80 liters trashcan technique for protecting the foot of each tree. Adding loam in the trashcan, creates a small heat sink.
Of course, if you have walls where you can plant nearby it makes both the heat sink and the hedge :) .

I used plastic sheets on wooden frames before to protect the feet of the trees. But in the winter, snow and rain would weight on the plastic and tear it up... just at the worst moment, of course. The trashcans are made of black plastic of sturdy quality. Snow won't break them.
For smaller trees that are still short, I just make a medium-sized hole in the bottom of the trashcan. If a branch just pokes through the bottom of the trashcan, the branch will fit in the hole and be kept intact . As the trees grow I broaden the holes, until I completely remove the bottom on the trashcans.

I would try the LDA in the ground. I have two LDA. One came with a tag from Baud and the other was bought as an unknown and I refer to it as "healthy longue d'aout". Both do now perform well (Baud's took much longer to adapt).
You may try to get an European BT, a Dalmatie too to try. My other trees are still under evaluation or are unknown strains, so not very useful in a forum discussion ...