A Christmas wreath

Hi,

I complemented him on a Christmas wreath that he had put on his door.

If . . .

i) I am mentioning the laurel wreath for the first time
ii) There is only one.

… is it still OK grammatically to say "a laurel wreath"?

I know "the" is definitely OK because it's specific enough (what laurel wreath? = the one he put on his door), but can I also use "a" if I am introducing this noun for the first time or if I mean "some laurel wreath" (the emphasis is weaker)?

Thank you for your help.

AO