Fashion shops stocking unknown fragrant plant (6)
I believe the answer is:
hyssop
'fragrant plant' is the definition.
'hyssop' can be an answer for 'plant' (hyssop is a kind of plant). I am unsure of the 'fragrant' bit.
'fashion shops stocking unknown' is the wordplay.
'fashion' indicates anagramming the letters.
'stocking' means one lot of letters goes inside another ('stock' can mean 'carry' or 'contain').
'unknown' becomes 'y' (algebra).
'shops' anagrammed gives 'hssop'.
'hssop' placed around 'y' is 'HYSSOP'.
Can you help me to learn more?
(Other definitions for hyssop that I've seen before include "Herb in the mint family" , "Small bushy plant with bitter minty leaves" , "little blue flowers" , "Aromatic plant" , "Plant with minty leaves used in cooking or as medicine" .)