I'm having a May afternoon outdoor wedding, semi-formal (guys in suits, not tuxes, h'ourdvre reception). Our colors are red, black, and ivory. Since we are trying to keep this more semi-formal, and I really just want to use the same flower throughout, a florist I met with suggested going with red Gerbera's rather than red roses to "tone down the affair". Would red and/or white roses create a too formal atmosphere since I want to keep it somewhat laid back?