I have a mail order Digitalis parviflora that I thought was way too small to start flowering but it's doing so anyhow. Is there definitive research or even "conclusive garden lore" on whether a short-lived perennials will last longer if I snap this year's flowers off? It seems that would force it to get a little more established. I have a fear it's going to put a lot of energy into blooming, the weather is going to turn hot and humid, and it's going to give up the ghost.