Our artichokes are still producing, and our three year-old speciman is rather spectacular. Artichokes were a bit problematic in our garden microclimate. We're in the Bear River canyon, which tends to be 4-5° cooler than our neighbors due to the accumulation of cool air. This means that even though we are at a relatively low foothill elevation, we accumulate frost amounts similar to gardens in Nevada City, at double our elevation.
The extra frost we get in winter has previously set back the plants, so that about the time they have resprouted in spring, they do not have enough cool weather to produce flowers. This year I covered them with floating rowcovers, and they kept their foliage though the winter. This spring we have been rewarded with several weeks of artichokes. It looks like we'll have at least one more harvest, maybe two if the weather cooperates!