The short opening suits a plant (6)
I believe the answer is:
thrift
'plant' is the definition.
(type of plant)
'the short opening' is the wordplay.
'short' means to remove the last letter.
'opening' becomes 'rift' (rift is a kind of opening).
'the' with its final letter removed is 'th'.
'th'+'rift'='THRIFT'
'suits a' acts as a link.
(Other definitions for thrift that I've seen before include "Practise this to save money" , "Care in using money" , "Careful control of resources" , "Being frugal" , "plants from cliffs by sea" .)