Mature is considered in flowering stage. I think the cops actually only consider mature to be close to harvest. I was told a grower had 8 huge plants close to harvest last summer. . A neighbor spotted them and called the police. Police showed up and confronted grower about his large plant count. The grower was then told to choose 2 plants, the police left with the others. In another incident, a grower had 16 plant in vegetative stage, the police showed up and confiscated all of them. It seems like it just depends on what mood the officers are in when they arrive. One of the biggest issues is theft. The teenagers ( and older thieves ) roam the countryside in early fall stealing plants. A friend had mature plants taken from her greenhouse. Police have to investigate these thefts when called, although they probably just go through the motions to satisfy the victims. Vermont recently passed a retail pot law allowing stores to open soon. I think this is aimed at our sizable tourist trade ( like Colorado ). Black market prices have plummeted in the past year as the state is flooded with homegrown.