Ask Mr. Smarty Plants

Wow ... that was a huge endeavour ... good for you, that is a garden feature that is going to change things on your property!  If you didn't have one before, you now have a "wildlife habitat" garden. 

You are right that you will have many volunteer plants, and not just below water level.  Any plant that can thrive in your conditions, whether it is native or alien (and perhaps agressive or invasive) will be battling for a foothold once the growing season starts (not to mention the weed seeds that have been released from the soil seed bank due to the construction).  It will be an important season for you to monitor the pond, as many of the "weeds" will actually be native plants that are appropriate for your ecosystem.

You haven't described the setting.  Whether you have carved the pond out of an opening in a woodland or it is in an open field will have some bearing on your plant choices.  What you will be trying to do is to create a pond ecosystem that mimics the ones occuring naturally in your area so go have a look at the neighboring ponds and see what is growing around them. 

Although the plants you install will ultimately be the plants you can access in the nurseries in your area, you can start the selection process by doing a Combination Search on our Native Plant Database.  If you select Pennsylvania, the type of plant (shrub, herbaceous plant, grass and so on),  light conditions, and soil conditions the database will generate a list of plants native to PA that fulfill those requirements.  Each plant is linked to a detailed information page that will give you images as well as information about wildlife attributes and is, in turn, linked to the USDA website.  You will want to choose a mix of shrubs, perennials and grasses.  If you leave mown or otherwise unimpeded access to the water, you WILL have geese move in and never move out.  Research on shoreline restoration indicates that geese like to be able to see the surface of the water from the shore, so planting shrubs and taller herbaceous plants really discourages them from settling in.

I recommend you also visit the Evergreen.ca database as they have a search feature for habitat gardens.  Although it is a Canadian resource, you will find that most of the plants they recommend that are native to Ontario, will also be native to your area of Pennsylvania (you can cross reference with the list you have generated from ours).  For example, when I search Ontario & pond edge a list of 171 plants is generated.  When I narrow the search to include erosion control (something you will be concerned with), the list is only 30 plants.  One of those plants is Cephalanthus occidentalis (buttonbush) which is also native to PA and on the list our database generates.  It is a good choice for your project.  Many of the dogwoods are also good choices.

It is a long winter in Pennsylvania so you will have many months to plan and learn before it is time to plant (and learn more!).  I recently discovered a website that will be a valuable resource for you called Ecosystem Gardening.  Sign up for their newsletter/blog and check out the links and books they recommend.  I particularly recommend a book by Carolyn Summers, titled "Designing Gardens with Flora of the American East" and Doug Tallamy's "Bringing Nature Home". Visit our Bibliography and search the topic "Wildlife" for more recommendations. 

I hope you will find this answer more helpful than the simple list of plants you may have been expecting.  Here at Mr. Smarty Plants we are big fans of "teach a man to fish, you feed him for a lifetime".  Enjoy the new gardening adventure you are embarking on!