The most common and most likely answer to this crossword clue is the 9 letter word GRASSLAND
I've seen this crossword clue in Independent
G
R
A
S
S
L
A
N
D
More clues leading to the result GRASSLAND
Buddy explains!

The straight part
We know that "growth area" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case growth area = grassland.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 GRASSLAND mean?
GRASSLAND noun- An area dominated by grass or grasslike vegetation.