Here is a list of Botanical Gardens in the US
http://en.wikipedia.org/wiki/L...

Here is a list of Public gardens around the world http://en.wikipedia.org/wiki/L...
I have not checked this one out yet but I hope it helps you find the ones near you

Here is another way to find a Public garden near you
http://www.publicgardens.org/g...

Please feel free to add your own list of public gardens
or web sites for your favorite gardens

Thx Sandy, I was trying to plan a spring trip to look at Iris gardens, trip planning is a good winter project.

My favorite, hands down is MOBOT in St Louis. Mercer in Houston is another very nice and large one. There's a couple good ones in the Quad Cities area - Van der Meer in Davenport, Ia. and Quad Cities in Rock Island, Il. Texas also has a smaller botanical garden in Ft Worth, there's a pretty good sized one in Galveston. Ft Worth also as a downtown Water Garden that is a site to behold.
Though the focus is more on butterflies, 2 said Butterfly Houses have ton's of tropicals; they are The BF House in Chesterson, western suburb of St Louis (site is a subsidiary of MOBOT) and The Museum of Natural History in Houston.

In Memphis there are some beautiful gardens, like Dixon and Goldsmiths but for travel I think about going up north. I have been to St Louis Botanical and Hausermanns in Chicago area. But I can't travel to far or to hot, no air travel either due to health, so I think Iowa sounds perfect. Thx, all.