The most common and most likely answer to this crossword clue is the 7 letter word BEGONIA
I've seen this crossword clue in The Guardian
B
E
G
O
N
I
A
More clues leading to the result BEGONIA
- Say nothing ousting mapmakers in Bosnia plant
- Bedding plant - a big one, unfortunately
- Almost clear off one initially aggressive plant
- Plant a big one criminally
- Away with you, nearly up-ending best plant
- Plant, a big one that’s monstrous
- Flowering plant, variant of a big one
- Go away shortly, vacation in Ibiza, seeing colourful flower
- Occupant of bed begs Sonia to untuck edges of sheets
- One bag I sent for recycling plant
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 = begonia.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 BEGONIA mean?
BEGONIA noun- Any plant of the large genus of Begonia.