Go here with a crowd, and come hungry. There are not only vegan options all over the place (almost everything on the menu is vegan), but there are also a LOT of raw options as well. The chef understands the subtle interplay of flavour very well; that is, he knows how to blend fresh vegetables with interesting herbs and spices.
The classification of "American" food belies his creativity. Because of the solid wall of variety that you're going to get, you want to bring a few of your friends, and order a different dish for each person, and share amongst yourselves. Try the Hibiscus iced tea. On a hot summer afternoon, this floral and calming beverage hits the spot. Also, give the Marakkesh sandwich a shot. It's a pile of crispy vegetables perched atop triangles of pita, topped off with a generous slice of avocado. It's served with a creamy (vegan, of course) avocado dip that you can drizzle over top of it to take it over the top. If you've got a taste for fire, each table has a shaker of grey salt and chili powder so that each diner can adjust things to her or his own liking.
Save room for dessert, though! On the night that we went, they had a raw strawberry cheesecake, a raw carrot cake, and a key lime pie thing. We ordered one each of the carrot cake and strawberry cheesecake. Because they were raw, there wasn't the exact replication of the desserts from when I used to eat the nonvegan versions, but the chef NAILED it when it came to replicating the experience of eating those foods. The subtle interplay between the cream cheese style frosting with the raisins and the cake was perfect (for the carrot cake), and the creamy and decadent cheesecake was just like I remembered it.
If you live in the area, give their raw cooking classes a try--you won't regret it! They also have a fairly decent reading library, where you can flip through progressive type books while you wait for your party to arrive. Trust me--go to Grass Root, and enjoy the whole experience of dining at a Tampa bastion of vegan delights!