Artichoke is not reliable to overwinter in Denmark. Different varieties are clearly more or less hardy. One of the most hardy is ‘Herrgård’, an old heirloom from Scania (southern Sweden). It is said to have been in culture for centuries in gardens of the aristocracy in Scania and Denmark. ‘Herrgård’ is probably identical to the danish ‘Serridslevgaard’, but I can’t tell for sure, as I havn’t got hold on the latter. Do you grow it dear reader, please let me have a cutting :-)
Many things have been written about the art of overwintering artichokes. Often by experts who never grew artichokes themselfes. Since I’ve overwintered my artichoke the last five years, I’m thus not an expert. I do it from a very simple theory. I believe moisture in the heart of the artichoke kills it at lower temperatures, and only at much lower temperatures will the temperature itselv kill the artichoke. Therefore I cover my artichokes with glass, with an inclination and earth touch towards west, as most wind and rain comes from that direction. The cracked pot is to keep down the glass in stormy weather. In case of severe frost I cover the glass and surroundings in snow, making an insulated hive for the artichoke. When snow melts, the glass leads water away from the heart.
In autumn i pot cuttings and store in the greenhouse as a sofecopy. I still didn’t have a truely cold winter on top of my artichokes. When that comes, with daytemperatures of -20 Celcius, I must be very carefull to add suficient insulation.