The most common and most likely answer to this crossword clue is the 4 letter word DART
I've seen this crossword clue in The Times
D
A
R
T
Buddy explains!

The straight part
We know that "Devon flower/spring" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case devon flower/spring = dart.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 DART mean?
DART noun- A pointed missile weapon, intended to be thrown by the hand, for example a short lance or javelin
- Any sharp-pointed missile weapon, such as an arrow.
- (sometimes figurative) Anything resembling such a missile; something that pierces or wounds like such a weapon.
- A small object with a pointed tip at one end and feathers at the other, which is thrown at a target in the game of darts.
- A dart-shaped target towed behind an aircraft to train shooters.
- A plan or scheme.
- A sudden or fast movement.
- A fold that is stitched on a garment.
- A fish, the dace.
- A cigarette.
- To throw with a sudden effort or thrust; to hurl or launch.
- To send forth suddenly or rapidly; to emit; to shoot
- To shoot with a dart, especially a tranquilizer dart
- To fly or pass swiftly, like a dart; to move rapidly in one direction; to shoot out quickly
- To start and run with speed; to shoot rapidly along