Garden Party Chic

I'm going to a wedding this weekend with the instructions to dress "Garden Party Chic."

Starting yesterday, I find myself stressing. I don't know what it means and I whatever it means, I don't think I have it. Linen pants? Searsucker suit? Polo and Khakis? A blue suit? Regular suit, no tie? Sportcoat and slacks?

Very confusing instructions. My favorite suit is a nice black with charcoal pinstripes. This is the suit that fits me best and the one I'd prefer to wear. But it is a bit fancy. So do I go for it without a tie? Or do I wear a dark blue suit - a lighter, summer suit I got in Korea? Or go for the gray suit? Or do I go slacks with shirt, more casual, etc. I just don't know.

Side note - a nice suit wearing article/guide found on the internet.