The most common and most likely answer to this crossword clue is the 5 letter word FLORA
I've seen this crossword clue in The Guardian
F
L
O
R
A
More clues leading to the result FLORA
- State I’d ignored to find vegetation
- Local plants I'd taken from coastal state
- Gut bacteria reportedly fell with onset of acidosis
- Market places once filled with large plants
- Plantlife I'd eradicated from US state
- Admitted by Italian monk, look at plants
- All the flowers are for her
- A German man’s climbing plants
- I’d quit the Sunshine State for this girl
- A Swedish boy possibly upset girl
Buddy explains!

The straight part
We know that "Vegetation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vegetation = flora.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 FLORA mean?
FLORA noun- Plants considered as a group, especially those of a particular country, region, time, etc.
- A book describing the plants of a country, region, time, etc.
- The microorganisms that inhabit some part of the body