Buttercup flowers,what should be done to the stem of the flower when the bloom has fell off?

Cut the stem just as the flower fades. You will be rewarded with more flowers.Buttercup flowers,what should be done to the stem of the flower when the bloom has fell off?
Unless you want seeds (and possibly the death of the plant), you should cut the stem off. It may re-bloom. If the plant is a re-seeder, and you let it go to seed, you may be rewarded next year with more plants.