The next time you find yourself in deep rough around the green, don’t fear! Simply treat the situation like you are in a green-side bunker!
When playing from a green-side bunker, you should swing aggressively and hit sand first. The same can be said when playing from deep rough, you need to swing aggressively, hit ground first and essentially dig the ball out of the lie. Be sure to also use a lofted club, preferably 56 degrees or more. My primary club from these scenarios is a 60 degree.
What I see from my students both in deep rough and in bunkers is a fear of the aggressive swing. I watch over and over small backswings and low speed swings in a situation that calls for larger and faster swings. Small and slow swings are great from lower grass in traditional chipping situations. But if you are in taller grass or sand then the swing changes to pitching or even flopping with a more aggressive nature and ground first.
Both from deep rough and sand, as long as you hit ground first and use the loft, the ball will not go far. The fear of the aggressive swing comes from the worry of catching all ball and sending it flying over the green. If this is true for you, you just need to spend time practicing ground-first contact and build that trust. Once you know that you can control the bottom of your swing and hit ground first every time, the fear of the bigger and faster swing should go away.
Whether in deep rough or sand, if you do the smaller chipping motion the ball will simply go nowhere, especially if you properly hit ground first. So then many players will keep the small motion and make the ball go further by making ball-first contact. This is a dangerous route and should be avoided. Trust the tall grass will slow down the club and be aggressive!
The final point to make is not every lie in the rough is the same. You should begin analyzing different lies in the rough and associate it with a percentage of carry distance loss. For example, I associate sand with a 50% carry distance loss. Some lies in the rough may be even more than a 50% distance loss, others will be less. If you have a deep lie that will create a 50% distance loss, use a lofted club, and hit ground first, the ball will not go far and requires a higher club speed.