Does anyone know whether removing the flower stems will promote and second production of flowers?
Not on the macrorrhizums. Phoebe Noble, whose book on hardy geraniums got many of us hooked on them says she never dead-heads the macrorrhizums and I have followed her advise. It also allows for reseeding to rejuvinate them. But I have also found seedlings 4 meters away.
I've dead headed mine and never had a second growth of flowers. If I don't dead head, I get too many seedlings in wierd places.