Hi Rose,
It's a pleasure to help, and thank you for pursuing this.
I suggest not using artificial state boundaries for your
"native" criterion unless the garden is supposed to be an
example of what grow in the state. It's too limiting and at the
same time too broad. Maryland has several physiographic regions --
all within the bay watershed. Many of the plants that thrive in the
western mountains are not suited to our coastal plain environment.
On the other hand, a plant that is native to Delaware's or Virginia's
coastal plain environment is likely to be very well suited to our
environment. Plants don't know about state lines.
Since you're thinking about butterfly -- i.e., ornamental -- gardening,
I'd like to send you a couple of publications of the Fish & Wildlife
Service entitled Native Plants for Wildlife Habitat and Conservation
Landscaping. The big one is 5 Mb, and includes thumbnail photos and
considerable (coded) information about each plant in the Chesapeake Bay
watershed judged suitable for landscaping. It includes the
physiographic regions and the states where the plant has been
found. The small one is 600K, is limited to the Coastal Plain, and
just lists the plants without a lot of detail. They're
both on the Web. I don't want to clutter up mailboxes, but anyone
who wants a copy can either google that title or ask me and I'll email it
to you.
Many native plants draw butterflies, at both the adult, charismatic
stage, and the juvenile caterpillars. The latter eat up the plants,
of course, but -- no caterpillars, no butterflies. Any plant with
lots of nectar, or juicy fruits will draw the butterflies. The
caterpillars are on a huge variety of plants, from grasses to
trees. I seriously doubt that the Arboretum's butterfly garden list
is limited to natives, though I haven't investigated it. For
instance, butterfly bush (Buddleia), one of the most popular
butterfly plants, not only is not a native, but is becoming
invasive. I finally got rid of mine when I found out how invasive
it was. On the other hand, butterfly weed (Asclepias
tuberosa) is a very decorative native perennial whose flowers will be
covered with butterflies, and one of the hosts for monarch
caterpillars. (It's a milkweed.)
These are just a few examples. I think what you need to do is start
defining your goals, and use those to define scope. There are many
publications and resources to look at once you have decided just what
you're trying to do. Mary Pat and I, as well as others, can give
you much better help when you have a better focus.
Jessica