The most common and most likely answer to this crossword clue is the 8 letter word ASPHODEL
I've seen this crossword clue in The Times
A
S
P
H
O
D
E
L
More clues leading to the result ASPHODEL
- Plant key behind reptile house
- Lily has a special house key
- A brick-carrier cuts short period in plant
- In old heaps, wild flower
- Plant takes a short while to camouflage brick container
- Plant key beneath reptile house
- Flowering plant acquired from shop, deal negotiated
- Lops head off flower
- Plant in hole with spade, not all nuts
- Lops head off 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 = asphodel.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 ASPHODEL mean?
ASPHODEL noun- Flowering plants of the family Asphodelaceae, especially Asphodelus ramosus and Asphodelus albus; the flowers of these plants.
- The flower said to carpet Hades, and a favorite food of the dead.