Ironically, this leaves too long, say, to provide more leaves! (3)
I believe the answer is:
tea
This clue could be a double definition.
'ironically this leaves too long say' is the first definition.
'tea' can be an answer for 'leaves' (as in tea leaves). I'm not certain of the remainder of the definition.
'more leaves' is the second definition.
'tea' can be an answer for 'leaves' (as in tea leaves). I am unsure of the 'more' bit.
'to provide' is the link.
Can you help me to learn more?
(Other definitions for tea that I've seen before include "Shrub; drink" , "Light afternoon meal" , "Meal/drink" , "going to pot?" , "Assam, e.g." .)