I would love to have a lot of lavender in the garden, but it just doesn't seem to do well enough here - or at least, I am doing something wrong. Lilacs are awesome though, as the flowers smell so great too, even though they don't last long. We have two lilacs, but one is going to have to go, as it is falling down and in a weird place.
I think the problem you have with the lemon is the same I have with everything. I am just not sure what to do for the winter.
The herbs go well in Finland for the short summer, and I like mint, basil, parsley and the like. We had rosemary last summer, but my wife doesn't like the taste. Strawberries are always on the list, and my daughter wants to put some in her garden area. We are going to build some boxes so they are off the ground and away from the rabbits and pheasants.
Leave some space for each of the strawberries to spawn their minions. Up to four-five in a chain per root per season I had.