The most common and most likely answer to this crossword clue is the 9 letter word HYACINTHS
I've seen this crossword clue in The Guardian
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More clues leading to the result HYACINTHS
Buddy explains!

The straight part
We know that "bloomers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bloomers = hyacinths.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 HYACINTHS mean?
HYACINTHS noun- Any bulbous plant of the genus Hyacinthus, native to the Mediterranean and South Africa.
- A variety of zircon, ranging in color from brown, orange, reddish-brown and yellow; a jacinth.