Hey ladybug-
Try this website. It may be able to help you contact some nurseries in Hawaii. The only thing is that they don't list what kinds of plants each nursery has. Hope this helps a little.

Here is a link that might be useful: Find Nurseries

Try one of the big plant sales, there is a much larger variety of plants available at the sales than there is at the garden shops. They just had a nice plant sale in Kona and I got a lot of small succulents to put in a terra cotta "strawberry" pot. Some of the orchid varieties are quite small, too and would do well in a terrarium.

Oahu has occasional plant sales in Thomas Square, but I'm not sure when. Which island are you on?