Economical management in the garden?

I believe the answer is:

thrift

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'economical management' is the definition.
'thrift' can be an answer for 'management' (thesaurus). I'm unsure of the 'economical' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for thrift that I've seen before include "Prudence in handling money" , "Economical management of money or resources" , "Being frugal" , "Extreme care in spending money" , "plants from cliffs by sea" .)

I've seen this clue in The Irish Independent.

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