A growing source of wooden blades (6)
I believe the answer is:
willow
'a growing source of wooden blades' is the definition.
I can't tell whether this definition defines the answer.
'a growing source of wooden' is the wordplay.
'a growing' becomes 'will' (I am not sure about this - if you are sure you should believe this answer much more).
'source' says to take the initial letters (I've seen 'sources of' mean this (the beginning of a word is its sauce)).
The first letters of 'of wooden' is 'ow'.
'will'+'ow'='WILLOW'
Can you help me to learn more?
(Other definitions for willow that I've seen before include "Sally tree" , "Water-loving tree" , "It produces osiers" , "Pussy- - -" , "Cricket bat wood" .)