The most common and most likely answer to this crossword clue is the 5 plus 4 letter word PLANE TREE
I've seen this crossword clue in The Times
P
L
A
N
E
T
R
E
E
More clues leading to the result PLANE TREE
- Intend to be in Paris to tour energy plant
- Aim to be in Paris, beginning to experience some urban life?
- Earth, possibly, about rear of large woody plant
- Arrange to be in Paris with English timber supplier
- Leaves on this, having intention to be in Paris by start of evening
- Earth, eg, and grass mostly being a feature of city park?
- Earth, say, on English sycamore
- Plant most of the grass on the trail of earth, perhaps
- Growth of scheme to be French and English
- Debts regularly seen to support scheme with regard to energy growth
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 = plane tree.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.