The most common and most likely answer to this crossword clue is the 9 letter word ASPARAGUS
I've seen this crossword clue in Independent
A
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More clues leading to the result ASPARAGUS
- Vegetable poisonous types take in a meat and tomato sauce
- Shoots soldier with sawn-off gun in SAS, unusually
- Some lumps, maybe, appearing back on a spring plant
- Like soldier from America clutching good spears
- Plant speared on one’s fork
- Saving time, cook pasta sauce with end of sausages and vegetable
- Vegetable served after a special introduction to Alan Sugar backfired
- Sweetheart turned up after a spring vegetable
- A southern state taking on dicey Sugar’s plant
- A box and a grand American vegetable
Buddy explains!

The straight part
We know that "vegetable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vegetable = asparagus.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 ASPARAGUS mean?
ASPARAGUS noun- Any of various perennial plants of the genus Asparagus having leaflike stems, scalelike leaves, and small flowers.
- The young shoots of Asparagus officinalis eaten as a vegetable.
- A green colour, like that of an asparagus.