Rampant disease no menace to house plant (7)
I believe the answer is:
anemone
'plant' is the definition.
(anemone is a kind of plant)
'rampant disease no menace to house' is the wordplay.
'rampant' shows that the letters should be reversed in order (rampant can mean rearing).
'to house' says the answer is hidden in the clue (I've seen 'houses' mean this (part of the clue houses the answer)).
'enomena' is hidden within 'disease no menace'.
'enomena' written backwards gives 'ANEMONE'.
(Other definitions for anemone that I've seen before include "Plant; marine creature" , "Pretty flower or sea animal" , "Kind of buttercup with white or coloured flowers" , "Plant of the buttercup family with brightly coloured flowers" , "bloom" .)