Obamafoodorama has two posts tied to tours of the White House Garden and stories resulting from it. Judging by the photo, the garden's doing well, although I can't say the same for the grass bordering it. One hazard of showing it off to lots of people I guess. It confirms that while they're using "raised" beds, meaning the dirt is hilled up, they aren't enclosing them with boards, which provides deeper beds.
I was surprised by the mention of artichokes, which I don't think of as growing in the area. Turns out an annual variety can be grown in zone 7, which the White House is in. Since I've never grown them, I shouldn't second guess, but they don't seem like a vegetable that maximizes productivity per square foot.
Since the President likes pie, it looks as if he'll get some rhubarb pie. Though again I'm a little surprised if they get significant production the first year out. But even one pie is worth it