Question
I am planting a cottage garden at our weekend house which is upstate just north of Westchester. There are numerous flowering perennials listed and I do have a few places I have located to buy the flowers. However, the grass or groundcover is still a question I have not been able to solve. What kind of planting should we do for the ground, if any? I don't mind grass, but I would like to "do it right" if there is a preferred ground covering.

Answer
I think you don't know what you're getting into Jerrie when you ask for the cottage garden groundcoverings.

Being an English concept, the cottage garden floor could be built of wooly thyme, pennyroyal, or chamomile. But check my previous answer to another question this week about "alternatives to grass".  Labor-intensive, English non-grass solutions all depend on your ability to throw money out the window at the humans needed to pluck weeds from the non-chamomile/pennyroyal/thymus serpillum.  

Do you have that kind of money?  

If not, I hope weeding is your idea of a good time and you have lots of friends who enjoy doing that with you - on your lawn.

I don't even know if sheep will eat pennyroyal.

I understand Buckingham Palace has a chamomile lawn. But last tourist I spoke to said it was not being weeded properly.  Times must be rough for the Windsors.

If however you actually pull one of these non-grasses off, you are guaranteed to have a very impressive cottage garden - walking thru it alone will provoke oohs and ahhs from visitors as the fresh minty fragrances waft underfoot and across the street to the neighbors.

Our local Old Westbury Gardens does not have a chamomile lawn in its cottage plantings.  Just the cottage and its hollyhocks etc. around the perimeter.  Ordinary Kentucky Bluegrass is the frame.

Worth doing?

That's a personal decision.

Let me know if you have any other questions on this matter, I love the cottage garden look.