Not everything in the garden can be so lovely, surely? (4)
I believe the answer is:
rosy
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for rosy that I've seen before include "Of the future, promising like flower" , "Blooming - hopeful" , "Blushing - optimistic" , "Pink; promising" , "Hopeful; blushing" .)