Pessimism is warranted only if you seldom see any butterflies within a few blocks of either site.

If you have Black Swallowtails in your climate, a container of dill and/or parsley will attract females to lay eggs.

Martha

Fennel is the best host plant in my experience with Black Swallowtails. Containers of Pearly Everlasting will attract American Ladies and False Nettles will bring in Red Admirals.
It may take a while for butterflies to find your refuge, but eventually they will. Bigger is better, so as many containers as you can get will help.
Butterfly Bush (Buddhlea) and Mexican Sunflower (Tithonia) are also excellent nectar plants.
Another thing you can do is get your neighbors involved. Share with them plants which attract butterflies (esp. Milkweed) to plant in the ground.
Swear off all pesticides, and if possible, have your neighbors do likewise. The more people you can get "hooked", the better your chances of seeing butterflies soon.
Good luck, and happy butterflying :)

John

Parsley is so easy to germinate and grow and the Black Swallowtail BF's seem to find it quickly. I have had them lay eggs on small seedlings that were still in their germinating pots sitting on my potting bench.

In my area, the Lantana proves to be a big draw for nectar and will grow well in a pot. Another nectar plant that is good for containers and will provide continuous blooms is Penta. In my area, I have to overwinter, as Penta will not survive our winters outside, but I would not want to be without Penta's in my butterfly garden. Deadhead the old blooms and feed lightly throughout the growing season and it will bloom continuously for you.

Mary

flat leaf and curley parsley seedlings:
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Potted Penta's:
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I wrote this handout for container gardening (see the link).

Here is a link that might be useful: Info on putting together containers

Well I haven't seen any butterflies at my home in a long while. Hence, the reason I'm creating a butterfly garden. There is one at the local library a couple of miles from my house. I will be quite discouraged if there aren't any inhabitants. The Penta might be a great addition as well as a few other containers. I like the idea of "the more, the better."

That photo was gorgeous, Mary. Thank you for sharing.

When should I see butterflies in my area? I live in the Piedmont of NC, very close to the VA border.

It depends upon your location. If you live near some open wild space or even within the vicinity of another butterfly gardener, chances are you'll see some activity soon.
However, if you're surrounded by miles and miles of "green desert" aka manicured, sterilized lawns, it may be awhile before you see your first set of wings.
This is where your neighbors come in as possible extensions of your garden.

John