The most common and most likely answer to this crossword clue is the 10 letter word AGAPANTHUS
I've seen this crossword clue in Financial Times
A
G
A
P
A
N
T
H
U
S
More clues leading to the result AGAPANTHUS
- Plant, one occupying a space like this
- Plant Khan, say, then sweep accordingly
- Plant article to fill a space like this
- Plant pot like this on cooker
- A bloomer putting vessel on cooker that way
- Putting vessel inside oven like this is a bloomer
- Bring up heroic tale about a vessel with a ruffian after getting rid of the good flowering 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 = agapanthus.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 AGAPANTHUS mean?
AGAPANTHUS noun- Any member of the genus Agapanthus of flowering plants.