The message
from Tim Nicholson contains these words:

Aaaargggghhhh. Pretty flowery names might do for a ditsy labrador, but
puhlease, give a border collie a proper dog name that it won't be
ashamed of in public :-) Traditionally, border collies use a plain
single syllable name.

Janet.

Such as Bo, Fig, Ivy, May, Pia, Sal?

Erm, Ivy and Pia have two syllables..collies can count, you know.
Classic monosyllable working-collie names are Meg, Nan, Moss.

Maybe Moss or Fern would do.

Incidentally, one of my retrievers is called 'Holly' - but Ditsy's not
in Chambers, and is a word I've not come across before. Which
particular Labrador trait is it describing?

Ditsy appears in my Chambers (Concise, 1991 edition).
"US colloquial; amiably eccentric, scatterbrained, precious, affected".

Janet.