For those who understand german or want to see a nice photo, there is an interesting post in Exoten und Garten about a grapefruit-looking tree in Chiavenna in Northern Italy, where winters can be quite cold. At least -10C. So it must be considered a nice citrus tree surviving in zone 8.

http://members3.boardhost.com/Exoten/msg/1329091298.html

The trees position in relation to microclimate can be better seen in this post:

http://exoten.dyndns.org/cgi-bin/archiv.cgi?function=2&index=E0606862D36C015F

The question is: Which type is it. Is this a grapefruit seedling ? (occational reports speak about grapefruit seedlings surviving a lot of cold, for instance in London. Or is it a citrumelo or a grafted variety of grapefruit ?

Please offer any insight to identify this tree, and please someone get grafting material from this apparently monofoliate tree, if indeed it survives more than -10C during the Siberian blast of cold that Northern Italy is going thru in these days.......

Michael, beautiful tree indeed!
Thank you for bringing that question here.
I don't have answer, let me just mention one more interesting area relatively nearby to Chiavenna, information brought to us by Mike/Citrange:
"The Lemons of Lake Garda"
link

http://translate.google.com/translate?sl=de&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fmembers3.boardhost.com%2FExoten%2Fmsg%2F1329091298.html

Page Google translated to English.

Looking at the leaves, it is not a citrumelo. The fruit is not ripe, it could be a number of different grapefruits.

One possible candidate is Sanford venasca. It is monofoliate and has grapefruit-like fruits.
/Robert

The Chiavenna Grapefruit tree is reported heavily frost damaged after the winter.

what a pity! it was a beautiful grapefruit tree indeed... the first link with the pics is down, hence i attached some of them... hope i'm not violating any of the copyright rules.

Wonderfull Tree !!!

Anyone knows how it is now ???