Tom Petty: He loved the garden, and he knew the name of every flower and every plant you walked by.
Int: So did he grow, like, really great weed?
TP: No, he didn’t.
Int: Actually we interviewed someone very close to McCartney once, and they said McCartney had two full-time botanists who were just devoted to growing his pot.
TP: Well maybe…George wasn’t really a pothead. He wouldn’t say no necessarily, but only on occasion. He really loved flowers, you know? I remember we were going by some flower - some plant once, and he said, “Tom look at this. ‘Cause I have pictures of these in my wallet.” [laughs] 
- Tom Petty interview with Sound Opinions (2003)