“Less is more” is from a Robert Browning poem though it is frequently attributed to the architect Mies Van Der Rohe as a precept for his minimalist design style.
“Less is a bore” was bravely ventured by architect Robert Venturi in the 1960’s.
Both are right, depending on the situation. Understanding how to apply one or the other is part of the landscape design process with the client and the designer.
The photos here are of the same residence, one of the front, one of the back. Less and more.