Sorry to say, but you are likely too late to have them produce for this year, but not too late to grow the plants. Artichokes need a cold period called vernalization to initiate flower stalk production. I'm in Cincinnati, and I start my seeds indoors under lights in January. I move them out and harden them off in mid March under frost blankets, and plant them the first week of April, covering them on freezing nights. Last season out of 28 plants, I had 10 that produced.
Artichokes can be perennial. Cut the leaves back in the fall after they are frost killed, put a small flower pot over the crown and/or bury it in leaves, straw, whatever. With luck it will resprout the next spring and will certainly produce flowers if it does. This has worked for me in years past, not sure how they will do with this epic winter we are having. Alternately you can dig up the roots in the fall and overwinter them like Cana Lily. Keep in mind the plants get quite large, even in the first year. Some of mine were at least 5 foot across, so give them a lot of space.
Lettuce: Succession plant in the bed every 3 weeks in early spring, every 2 weeks getting into may and June. Don't be afraid to start them indoors as well. It grows great in containers, which can be moved into shaded areas as things heat up. Its just not worth messing with come July, it won't do well in the heat and dry soil. Check out New Zealand and Malabar spinach for summer greens. Start planting again in September, and make sure you keep it irrigated. You should get harvests through October, even well into November with row cover or a low tunnel. Happy growing!