Quite a few medieval manuscripts list the relationship of the herb to the stars. I've seen this quite frequently. Usually they refer to it as the ruling planet or ruling star and each plant has one.
I think it's entirely possible that plant attributes, ruling stars, and other "properties" or "temperaments" have been assigned to plants (and perhaps even bathing practices) within the VMS. I've assumed all along that this is a possibility as it was common practice in the Middle Ages to believe that everything was governed by the stars, but determining HOW this information might be codified is the difficult part and you haven't really given an example of exactly how you think the Voynichese text translates to meaningful information.
I think it's entirely possible that plant attributes, ruling stars, and other "properties" or "temperaments" have been assigned to plants (and perhaps even bathing practices) within the VMS. I've assumed all along that this is a possibility as it was common practice in the Middle Ages to believe that everything was governed by the stars, but determining HOW this information might be codified is the difficult part and you haven't really given an example of exactly how you think the Voynichese text translates to meaningful information.