Definitely micro climates for lemons - against a warm protected wall is best! If you have snow or heavy frosts that could be a real issue, unless you want to do what they did in the old days and light fires amongst the orchards! But I'm sure certain varieties and microclimates woudl do better than others.

As for my artichokes, goodness, they are thistles, and I would say neglect worked for me! Actually, because of their location, I often spread the straw from the chook coop around there when I cut them down after the season, acting as a mulch against weeds of course but clearly chicken waste helps them along a little - also I chuck a handful or two of blood and bone on them once in a while.