Nestled Down: If the ball is sitting down, a 7-iron is the longest club I'd consider using. You need loft and clubhead speed to get it out.
Sitting up: If the ball is on top of the grass, use a normal swing but be ready for a flyer, especially if the grass is dry. I take one less club.
Playing from deep grass is a fact of life in professional golf. Tour courses are set up so hard now, and they're very penal for tee shots that miss the fairway. Some of the courses you play are no different. You have to know how to read your lie and take a calculated risk when you hit out of the rough.
If you aren't sure if you can get the club on the back of the ball cleanly, a cut shot is a great play. Play the ball slightly back in your stance, and account for some left-to-right curve when you pick your target. Opening the face will also give you some more loft, which helps in the tall grass.
Do not release the club early in the rough. If you don't retain your angle like I am in the pictures here, you'll make too much contact with the grass and lose clubhead speed. Resist the temptation to lift the ball out. Instead, rely on the club's loft and open clubface to do the job.
Because of the grass and open face, I take one more club for shots from the rough, unless the ball is sitting on top of dry grass. Then, I use more loft and swing softer, trying to hit it about 70 percent to avoid a flyer over the green.
Ernie Els writes instruction articles only for Golf Digest.