To check I've just got one of my peeps to water the flowers in the updated game. I'd already got the trophy at the beginning, so didn't get it again.
Click to reveal..
The important thing is to drop the peep in the right place. Drop the peep right in the middle of the circle made by the coiled hose, not on the watering cans or nearby.
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To err is human; to arr is pirate.