Plant boss sacking staff leads to acrimonious trade union meeting (8)
I believe the answer is:
ageratum
'plant boss' is the definition.
'ageratum' can be an answer for 'plant' (I've seen this before). I'm not sure about the 'boss' bit.
'sacking staff leads to acrimonious trade union meeting' is the wordplay.
'sacking staff' becomes 'ager' (I can't explain this - if you can you should give a lot more credence to this answer).
'leads to' says to take the initial letters.
The initial letters of 'acrimonious trade union meeting' is 'atum'.
'ager'+'atum'='AGERATUM'
Can you help me to learn more?
(Other definitions for ageratum that I've seen before include "growth" , "Plant with flowers of purple" .)