She's a Welshman's to the very end! (5)
I believe the answer is:
daisy
'she's' is the definition.
'a welshman's to the very end' is the wordplay.
'a welshman's' becomes 'dais' (Welsh name).
'to' means one lot of letters go next to another.
'end' says to take the final letters.
The last letter of 'very' is 'y'.
'dais'+'y'='DAISY'
(Other definitions for daisy that I've seen before include "Composite" , "See 1 Across" , "Plant; girl's name" , "Grassland flower" , "Grassland plant" .)