Hi all, Thanks so much for all the feedback! In the meantime, I did find one other interesting resource: ENature.com. There are all sorts of ways of searching, including by zip code. It's not terribly convenient, once you have the results, but it's still interesting. I have another plant that I'd be curious to know the identity of, if anyone knows it. It's in the last two photos of this entry, with one closeup shot and one distant shot. I thought it was flowers when I first saw it, but up close, it almost looks like some sort of succulent (?). It was growing in the marshes beside the Delaware Bay - the structure visible in the background of the last shot is actually a ramp to a handicapped-accessible viewing platform to look out at the water (and it's a horseshoe crab sanctuary, so out on the spawning horseshoe crabs at the right time of year) less than 50 ft from the tide line.

Muscadine leaves are thin and glossy both top and bottom. In Maryland they are only found in the eastern half of the state and not very common. They do not have a peeling bark, your pic is not muscadine. If you're lucky you have V. labrusca or Fox grape. Leaves thick, firm and with light colored felt on bottom. For us grapes are blooming now. Your state may have 10 or more grape species. Only the two mentioned above are edible. Grape vines are dioecious, if you have a vine with only male flowers there will be no fruit.

You might want to scan through the grape posts on the Fruits and Orchards Forum, but it seems that "Jupiter" is a highly recommended variety and is stated to be hardy to Zone 5. If I had room, I'd probably give that one a try.

That is caused by blister mites and will not harm the fruit. Stylet oil will kill the mites.