Economical plant? (6)
I believe the answer is:
thrift
'plant?' is the definition.
(type of plant)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for thrift that I've seen before include "Careful control of resources" , "Plant - saving - economy" , "Careful management of money" , "Prudence in handling money" , "Economy, frugality" .)