The most common and most likely answer to this crossword clue is the 9 letter word AMARYLLIS
I've seen this crossword clue in Independent
A
M
A
R
Y
L
L
I
S
More clues leading to the result AMARYLLIS
- Flower a daft male pulled up
- It’s unwise to force a climbing plant
- Foolish Hindu god returned flower
- Lily takes a walk and is crossing railway
- Shelf put up to support a girl’s plant
- Foolish god offered up lily-like flower
- Put up foolish thing on stage concealing top plant
- A foolish strike arising in plant
- Object of devotion universally adopted is flower?
- Old woman held in Arkansas over foolish bloomer
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 = amaryllis.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 AMARYLLIS mean?
AMARYLLIS noun- The belladonna lily, Amaryllis belladonna, native to South Africa.
- A similar lily in genus Hippeastrum, such as Hippeastrum puniceum, and cultivars.