I agree with Sherri, Washington Oaks State Park is another really beautiful garden to visit, both intracoastal and Atlantic ocean side. No gardens on the east side but the ocean views are amazing and if it's low tide, a beautiful place to take a stroll on the beach! It's one of my favorite places although since we've moved farther south I doubt I'll ever get up there anymore.
I've passed by Hammock Gardens Nursery many times as we've driven along A1A but never visited ... always wanted to stop but hubby was always in a hurry.