The groundskeeper gives you shears to remove the bugs from the obvious plant.
Use the shears on the obvious plant to start the puzzle.
This is the low-spoiler guide for "Shearing the plant" puzzle in The Darkside Detective - A Fumble in the Dark. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.