Out-of-the-ordinary fruit trees can be found at Frankie's nursery in Waimanalo. Native Hawaiian plants can be found at Hui Ku Maoli Ola in Waimanalo (incidentally, they supply Home Depot with tha majority of their natives). There are many other nurseries around that specialize in certain plants but those are two that I know right off the top of my head. Aloha!

On Oahu, try Kilgo's on Sand Island Access road as well as the Star Market by the University.

Sharon's Nursery in Waimanalo is another good one. They also have a map that shows all the nurseries in the area. There are a ton of nurseries all tucked away right in that area. Quite an exciting,unexpected find while out exploring one day!

Check your paper for plant sales. Lyon Arboretum has the best sales-- dozens of participating nurseries and hobbyists under one roof (Blaisdell Exhibition Hall), lots of rare and unusual stuff: orchids, bromeliads, gingers, heliconias, cactus & succulents, fruit trees, herbs, ti leaf, aquatic plants, anthuriums, ferns, native plants etc. etc. Also the Oahu Nursery Growers Association (ONGA) has several sales during the year, usually in Thomas Square Park. Great prices, and more variety in one place than if you go to any of the individual nurseries.