Butia of any species would have a difficult time in zone 7a however if your summers are hot and winters dry it might do alright with protection on the coldest nights.
Butia is marginal here in zone 8a and 8b but we do have wet rainy winters and that is tough on the centre spear of any palm.
Chamaerops humilis likes dry conditions but thrives here in the PNW. It is a long term palm here with many in the ground for years. I would say this is a better bet for Kentucky.
Sabal, trachycarpus, chamaerops, butia, brahea, chamaedorea and jubaea are fairly common here in Vancouver.
You see streets lined with Trachycarous fortunei all over Vancouver and the odd street with Chamaerops humilis.

The most northern established palms I know of are the two T.fortunei growing in Sitka,Alaska since 1992. I recieved the latest edition of HPI today and there was a very nice pic. of them in there. They are very healthy looking palms for growing at such a northernly latitude. They have never been protected. Cheers, Joe

That is amazing 😯 Alaska palms, hmmm.....maybe I will have a chance 😆 Joe can you put up a pic of them 😀

What does HPI stand for?
Maybe they have an online version (to get Alaksa palm pics)?
Barb

HPI (Hardy Palm International) a quarterly journal released by PNP&EPS (Pacific Northwest Palm & Exotic Plant Society) and available to members of that society. There are no on-line versions of the journals. You can however join the society for $40 annually and recieve those quarterly journals. All are full color with good articles mainly directed at exotic gardeners around the areas west of the Cascades, although not exclusively so.

http://www.hardypalm.com/

Cheers, Barrie.

Thanks Barrie.
They certainly cover topics we're all interested in!

I clicked on the link
http://jisao.washington.edu/pdo/ on Pacific Decadal Oscillation (nino/nina winter temps). Great stuff!
Barb

IDK where he lives in KY but a friend of mine here in northern KY has some 15 ft jellys and some other very large palms all ground planted.. they do get a tent over them in the winter and some xmas lights to help with the moisture control but that is about it. This is in Louisville KY zone 6B. I know alot of people on this forum are in colder zones mostly 5 but Here in 6B I don't see the need for all the protection. our lowest night has only been 20F so far and I have no damage at all to any palms outside. they have bags over them and thats it. If those large jellys are still alive down there then it should be fine. I have 5 single leaf seedlings from that jelly ( started with about 20 they all died on me ) so hopefully after all these winters they have some extra hardyness in there genes

A word Alaska means cold, but don't get fooled by that! Let's face the facts: they have way warmer winters than me, for instance, so no wonder that Trachys are not protected at all. Check their weather forecast. It's just warm up there 8)