I've had Red Flame outdoors the past two years with no winter injury. We had a mild winter, ~15F extreme low this winter. I expect it to be fully hardy here as we are very rarely below zero.

It is a good crisp grape, sweet and pretty early maturity. It's also a strong growing vine and bears heavily at an early age. I won't give up yet unless you get below zero regularly.

Figs aren't hardy here except in the most favored locations. There are some hardy pomegranates here but not many.

Maybe then there is still hope for my 'Red Flame' grape vine! It is right in the open ...not against anything & trying to train it up on some wires for an arbor. No we are rarely below zero either but do get down to the teens & low 20's sometimes. In the 70's we got a record low of minus 17 degrees & yet those old seeded Concord grapes survived that as did the pomegranate ('Wonderful') though it froze to the ground & came up again from the ground. Our wisteria tree that is over 50 yrs. old had lots of flower buds this spring but the last 'teens a week or so ago froze those first blooms; will flower off & on all summer though!

My "Flame" does fine in zone 6, and has survived -8F!

It is planted along the southern wall of the house, in a protected courtyard. I sometimes have had to protect the new growth in spring if it leafs out too early. The leaves and thinnest growth also usually get zapped by the first fall frosts while still green.

Since it's been in the ground since 2011 I've only had a few clusters of grapes, which are delicious, but this vine has definitely done the best of all I've tried (mostly American varieties). Part of this is due to the location I think.

Good luck with yours...

Thanks 'fabaceae' ... that gives me still hope then if you then live in a zone 6 in New Mexico! I live right at 5200 ft. in the city ..zone 7 but relatives in Roswell at about 3500 ft. elevation (?) seem to be in zone 6 but they can grow ocotillo & others in that colder zone than we can! I did go out & try & flex some of the 'Flame' vines .. some snapped/dry but a few did seem flexible & still alive! I do wish now I had planted it on the south facing side of a block wall too.. but thought making an arbor with it would be rather pretty... The VERY old Concords are west facing against a chainlink fence w/slats & they seem indestructible thank goodness! Even being seeded, that old Concord flavor is SO good... seeds & all! The new seedless Concord is leafing out and am anxious to taste those in a couple years to compare to the old seeded Concords! After the minus 17 or so, the Concords that year had weird- very alive but shriveled- green leaves all year & some fruits... but snapped back to the regular look the following year... indestructible- like our 50 yr. old pomegranates & fig! Hope you have a great crop of the 'Flames' this year... they don't get as big as those sold in the store though do they? Heard commercial grown Flames have been sprayed to get the larger size!

Natural Flame berries are medium size. Big enough. Commercially they are sprayed with plant hormones to first thin berries and open the cluster then sprayed again to size remaining berries. Later the trunk is girdled to get the largest berries possible.

They are pretty easy to root from dormant cuttings if you want more plants.

How far advanced are your Flames? Mine have about 6-8 inch shoots and they say 28F tonight. I'm hoping to save them but not sure how.

'fruitnut': oh, -if still alive- the 'flexible' vines still haven't begun to show any fresh buds! Same weather here... was 32 here this morning but temp dropped as the sun came up & to be cold (above feezing though) today. Wonder if I put a blanket around the main stem coming out of the ground if I could save the main plant at least?! Think we lost what fruit (apple, cherry, peach) that had survived the previous snap earlier) but had set small fruit so may have been OK. Know the earlier blooming plum & apricot blooms froze though! Interesting your note about rooting some cuttings.. have never tried to root cuttings of any kind except from houseplants, but may try some!
Thanks!

Any freeze this time of year will very likely only hurt the new growth and fruit. It won't hurt anything that grew last year or the trunk. Vinifera grapes are typically taken out in winter by temperatures near or below zero. Some like Concord are hardy to 20 or 30 below.

I wish I could try to grow Red Flame here near Chicago.

Vieja:
I assume "in the city" means Abq... I'm in the Santa Fe area. You're substantially warmer there, and I am always amazed at what I see thriving there that I only dream about!

The flame grapes have been sized about as I expected, not grocery store size, but not any smaller than any of the other locally grown grapes...

Again regarding your zone and grape hardiness, I would bet any lack of success is due to things other than cold. Most any grape cultivar should survive the winters where you are...

fabacea_native: Yes I live right in the heart of Albuquerque & a sign says '5200 ft. elevation' at the foot of our street! The 50+ yr.old Concord (seed) vines have survived our minus 19 degrees in the 1970's & our 9 degrees a year ago really damaged the leaves that following summer but they came back this last summer with loads of those delicious grapes. I checked the Red Flame today & found a few long branches that bend ok without breaking.. so hopefully those are still alive! Other grapes just now are sending out new leaves so it is still early it seems. Here in the City even the elevations vary from foothills to the Valley & all in between... so many microclimates to contend with just in the City!