The most common and most likely answer to this crossword clue is the 6 letter word MOWING
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More clues leading to the result MOWING
Buddy explains!

The straight part
We know that "lawn maintenance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lawn maintenance = mowing.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 MOWING mean?
MOWING verb- To cut down grass or crops.
- To cut down or slaughter in great numbers.
- To make grimaces, mock.
- To put into mows.
- The activity by which something is mown.
- Land from which grass is cut.