you gotta cut at the foot (c), then rubberband the foot to a piece of rubble. or if you can, scrape the foot off the rock and superglue it to a rubble. you can only superglue it if there is some rough spots on the foot, because they get really slimmy and superglue won't take at the foot.
best way though, is to take some bigger pieces of rubble and place it next to the stalks. they will naturally attach themselves onto the rock and you can give those away!
btw, if you cut the foot and leave some flesh on the rock (c) right where you have the yellow line, it will regrow a new head in a week or so...