The most common and most likely answer to this crossword clue is the 11 letter word LANCASTRIAN
I've seen this crossword clue in The Sunday Telegraph
L
A
N
C
A
S
T
R
I
A
N
More clues leading to the result LANCASTRIAN
Buddy explains!
The straight part
We know that "Person attached to house with red roses" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case person attached to house with red roses = lancastrian.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.