Annual poppies are easy to grow from seed, and I'm thinking if you're in zone 7, you might want to sow the seed in the fall. The seedlings can overwinter well, even through snow and freezing and then they grow quite quickly in the spring. I've had California poppies and Shirley poppies self-sowing in my yard for several years now, and the seedlings are usually less than an inch high in the fall, then they just hold on till spring and really start growing in late March. The first year I had them, I started with a spring sowing and they did flower in the summer, but they're a cool-season annual and the heat makes them get ragged. It's possible you could sow some right now and get some good blooms before mid-summer.

Also, they don't seem to transplant very well (it disturbs their taproots), so growing them in containers and then setting them outside isn't always a great idea, although I keep trying it out with some special CA poppies (they were a bit stunted last year, but I'm hoping for better this time).