The most common and most likely answer to this crossword clue is the 8 letter word POKEWEED
I've seen this crossword clue in The Times
P
O
K
E
W
E
E
D
Buddy explains!
The straight part
We know that "grower" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case grower = pokeweed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does POKEWEED mean?
POKEWEED noun- A poisonous North American plant, Phytolacca americana, with reddish stems, broad leaves, clusters of white flowers, and dark purple berries.