Plant lots of broccoli heads in spring? A lie! (7)
I believe the answer is:
lobelia
'plant' is the definition.
(lobelia is a kind of plant)
'lots of broccoli heads in spring? a lie' is the wordplay.
'lots' means to remove the last letter (I've seen 'lots of' mean this (the majority of the word)).
'heads' says to take the initial letters.
'in' indicates putting letters inside.
'spring? a lie' becomes 'lelia' (I can't explain this - if you can you should give a lot more credence to this answer).
The initial letter of 'broccoli' is 'b'.
'of' with its final letter removed is 'o'.
'o'+'b'='ob'
'ob' inserted inside 'lelia' is 'LOBELIA'.
Can you help me to learn more?
(Other definitions for lobelia that I've seen before include "something flowery" , "Garden plant with five-lobed flowers" , "Popular bedding plant" , "Showy garden flower" , "One of the bellflower family grown as a bedding plant" .)