When is it too late to plant alfalfa in the spring?

This spring of ‘19 is a brutal one! I have a 20 acre field that I need to get planted in forage oats, alfalfa, and orchard grass. It’s mid May and still too wet to work ground. The ground had beans last fall. Now it’s lush green with chickweed, grass and other weeds. Going to try to spray Gly today. Rain forecasted tonight and then every other or third day after that. If the liars are correct in their guessing game, aka weathermen, then it could be up to ten more days until the ground is dry enough to plant alfalfa.

Also I have been told there is a residual of ten days on 24d. I would hate to add the 24d to the Gly to get a better burndown but it’s so late that if there’s no rain then I don’t want to wait on the residual.

When is it too late to plant alfalfa in the spring?