Prickly Lettuce

Lately I've been trying to make the outside of our house look more...homey/less embarrassing. When we moved in (2 years ago this May) the front lawn looked nice (despite the dead tree in the middle of it) and there were two pretty flower beds. Since then we've planted a Red bud, taken out the dead tree, and planted a maple (that grew up in our untended flowerbed) However, our lawn now has a strict more weeds than grass policy, and our flowerbeds have turned into bare dirt and weeds with only a few hardy plants left that survived our negligence. After several days of weed-pulling and the addition of new mulch one of our flowerbeds now looks like this:

I'm pretty proud of it.

Now, I have to say, I'm pretty good at pulling weeds (and baby trees) and getting the taproot out and all...but one weed I can't seem to ever pull out is this one:

My roommate says she can pull them out no-problem, so I left them for her ;) I don't know how she does it though, as every time i try to, their prickly hollow stem breaks right off and all this nasty milky-white juice drips out. Of course, I had to know what on earth this weed was, so I finally googled it. I'm 99% sure now that it's a plant called "prickly lettuce" Identified not just by it's milky-hollow stem (apparently lots of plants have that) but by these spines on the underside of it's leaves (another reason these are a pain to try and pull.):

Now here's the interesting part. First of all the leaves are edible (I'm not gonna try them) and that milky stuff I always avoided because I assumed it would irritate my skin is actually good for sunburns. Oh ya, and it's a narcotic drug.
From this site: "The dreamy effects are a little bit similar to opium, but milder. Wild lettuce can help reduce the feeling of restlessness, excitability and insomnia."

Another site is filled with more fascinating stuff. "...it is still used for making a lotion for the skin useful in sunburn and roughness. The Ancients held the lettuce in high esteem for its cooling and refreshing properties. The Emperor Augustus attributed his recovery from a dangerous illness to it; built an altar to it, and erected a statue in its honour. "

Good to know. I still want it out of my flowerbed.