Of course, above all else Shatner needed to ensure that Phil’s voice sounded humorous to mesh with Aliens Ate My Homework’s other kooky elements, but it’s commendable that he went the extra mile by doing his own homework on plants.
I recently had the pleasure of speaking with William Shatner about his time on Aliens Ate My Homework and other areas of his career, and when I asked about how he prepared to play Phil the Plant, he recalled his deep scientific dive into the life within trees.
This subsequently allowed him to get into the mindset of what a plant might sound like if it was talking, though I would imagine that the other vegetative members of Phil’s species don’t drop nearly as many puns as he does during the movie.