I received a Judith Hindle, Dania's Delight, and a Northern Purple Pitcher from cobraplant.com a few weeks ago. They are doing great on a window sill sprouting new pitchers (too cold here yet for outside). My question is, should I keep the existing pitchers that came with the plants? Will they turn green again and grow, or should I cut them off? The new pitchers are already taller then the existing ones!