I know that many folks do not like "fake" plants but the industry is making silk and artificial plants so very lifelike nowadays. Since it would be impossible to watch every pet owner and pet in the waiting room (and especially if liability is an issue) maybe you should consider placing silk plants and flowers in those planters; a plus is that they would not need to be watered or tended except for a little dusting once in awhile! You could always have a few live plants behind the counter, placed up high on file cabinets or shelves ... but then again, if you have resident office kitties like my vet's office does that might not be possible either since cats like to climb and jump.