The most common and most likely answer to this crossword clue is the 10 letter word HYDRANGEAS
I've seen this crossword clue in The Daily Telegraph
H
Y
D
R
A
N
G
E
A
S
More clues leading to the result HYDRANGEAS
- Field covered with variety of shady shrubs
- Shrubs faring badly in ashy gardens garden
- Shrubs in shady ground either side of mountains
- She and Gary disastrously will make bloomers
- Cover up QPR broadcast bloomers
- Unusual garden has to include the latest in fancy shrubs
- A shy criminal will import wild garden shrubs
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 = hydrangeas.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 HYDRANGEAS mean?
HYDRANGEAS noun- Any of several shrubs, of the genus Hydrangea, having large clusters of white, pink or blue flowers