Small empty township surrounded by marine plant
I believe the answer is:
sweet pea
'plant' is the definition.
(sweet pea is a kind of plant)
'small empty township surrounded by marine' is the wordplay.
'small' becomes 'wee' ('wee' can be similar in meaning to 'small'**).
'empty' says to hollow out the word (remove centre letters).
'surrounded by' indicates putting letters inside.
'marine' becomes 'sea' (I've seen this before).
'township' with its centre taken out is 'tp'.
'wee'+'tp'='weetp'
'weetp' put within 'sea' is 'SWEET PEA'.
(Other definitions for sweet pea that I've seen before include "Peseta we paid for climbing garden flower" , "flowering plant" , "Climbing plant with butterfly-shaped flowers" , "Climbing plant with pastel-coloured flowers" , "Eat, weeps and gets climbing flowers" .)