The most common and most likely answer to this crossword clue is the 5 letter word TRENT
I've seen this crossword clue in The Guardian
T
R
E
N
T
More clues leading to the result TRENT
- English river split after junction
- Little Nell’s family unit finally split
- Flower rook brought into shelter
- River discovered by Rex, camping?
- . Wine opened by head of RBS for banker
- River runs through camping shelter
- Rector apparently camping at religious council
- Time musical is current
- River Test’s first opening
- Tory leader on board for English flower
Buddy explains!

The straight part
We know that "English flower" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case english flower = trent.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.