Plant information about aged staff (9)
I believe the answer is:
goldenrod
'plant' is the definition.
The answer is an example.
'information about aged staff' is the wordplay.
'information' becomes 'gen' (gen is a kind of information).
'about' means one lot of letters goes inside another.
'aged' becomes 'old' ('old' can be similar in meaning to 'aged').
'staff' becomes 'rod' (I've seen this before).
'gen' placed around 'old' is 'golden'.
'golden'+'rod'='GOLDENROD'
(Other definitions for goldenrod that I've seen before include "Plant with tall spikes of yellow flowers" , "Autumnal flower" , "bloomer" , "Plant with spikes of tiny golden flowers" , "Yellow-spiked garden flower" .)