The most common and most likely answer to this crossword clue is the 10 letter word WATERMELON
I've seen this crossword clue in The Guardian
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More clues leading to the result WATERMELON
Buddy explains!
The straight part
We know that "Plant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case plant = watermelon.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 WATERMELON mean?
WATERMELON noun- A plant of the species Citrullus lanatus, bearing a melon-like fruit.
- The fruit of the watermelon plant, having a green rind and watery flesh that is typically bright red when ripe and contains black pips.
- An environmentalist with socialist leanings (from the similarity to the fruit, being green on the outside, and red (Communist) on the inside).
- A pinkish-red colour, like that of watermelon flesh (also called watermelon pink).