The most common and most likely answer to this crossword clue is the 7 letter word MANIHOT
M
A
N
I
H
O
T
Buddy explains!

The straight part
We know that "variety of spurge" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case variety of spurge = manihot.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.