1st time gardener...please help?

There are some lively varieties of perennial hibiscus that survive the winters here in Southern New England (zone 5), so you should be able to find one that will work in PA. They come in all kinds of colors. I need to get a couple more for my yard as well. Annual flowers like marigold and zinnias can still be started from seed in the garden but it's late. Getting flats of annual flowers is going to be fairly slim pickings now, too, since many of them have been being sold for over two months now, but you can still find them. Pinch out any flowers on the ones you buy in 6 packs now. Better they spend a bit of time putting out roots rather than flowering for a few weeks. But before you start planting perennials (besides, at this point it may be better to wait until the worst of the summer heat is over before planting them) now, spend the summer looking at what is already in the yard. Look at websites for gardening (Better Homes and Gardens, White Flower Farm are good ones) to get an idea of what mature permanent plants look like, and what you like. Planting perennials is a good investment, as long as you like the mature plant. It can get expensive buying plants that don't do what you want five years down the road that you end up tearing out and replacing. See what may be available at local garden club sales (our library just had a book and plant sale yesterday where people cleaned out extra perennials and donated them for the library fund and there were some good buys), and look at other people's yards. If you see something you like, stop and see if the homeowner will show the yard to you and talk about what's planted to you. Not all will, but a lot of people are very proud of their yards and surprised enough that someone likes it enough to stop and ask.