Homestead Gardens is a beautiful place to visit even if you don't need to buy any plants. They have the most beautiful selection. We first visited last fall and even though I was visiting just to get ideas, I ended up buying these deep crimson mums. They were enormous and not too expensive. Homestead Gardens also does the neat little programs for kids with trains and pumpkins and whatnot. They also have a landscaping division if you need help designing and figuring out what to do with your yard.
They also have a little "club" with the plastic card for your wallet so you get the "special" rates for buying your plants. One catch, you have to buy at least one thing every year in order to keep you in good standing.