Faced with a bumper crop of turnip greens, I decided to freeze the greater part of the harvest. This method works well for most greens, except for spinach which only needs a few seconds in boiling water.
Wash and trim your greens. Turnip greens must be removed from the stalk. I don't bother with chopping as they tend to tear as I strip them, but if you prefer chopped greens I find it easier to manage after blanching.
Bring a large pot of water to a boil. meanwhile, have ready another large bowl filled with ice water. Submerge the turnip greens for 2 minutes, then remove with a slotted spoon (may as well re-use the water if you're preparing a large number of greens) and place in bowl of ice water. When greens are cold, drain well.
The greens should have some water on them, but not enough that you will be packing them in ice. Squeeze any excess out lightly with your hands, then pack in a freezer bag. Remove as much air as possible, then tape closed in addition to the seal. I like to double bag mine just for the sake of preventing air getting in, but that's me. Label the greens and use them withing six months or so of freezing.