Welcome to ATP, Cheri!
If it is this plant, maybe
@KurtMN would say how he deadheads his.
http://garden.org/lists/plant/...
Plant ID: 610592
Also (this is just a thought), after you get a solid answer, it would be a great kindness to add a comment to the plant in the database, explaining the best way to deadhead them.
I didn't find any "parent plant" entry in the database for
Gomphrena or Globe Amaranth, but that would have been a great place to find or add a comment that applies to all those plants.
