I've had a lot of success with cassia/senna, which is a host plant for sulphur butterflies. And I think all the passifloras/passionvines are hosts for our state butterfly, the Gulf Fritillary, and also for Zebra Longwings, which are my faves. The corky-stemmed wild passionvine is sort of a weed and I usually find it growing wild in lots of places. Not sure if anyone sells it, but you can collect the little fruits and start your own. If you're lucky, you may already have some growing.

And porterweed is a good nectar plant, as is mistflower/ageratum. The butterflies all like spanish needles/bidens alba, but the seeds are such a nuisance and it gets scraggly so fast.

Lantana is also a good nectar plant.

Carol, your FL native senna is what species? Not "all the passifloras" are FL native. What is are the species of FL native porterweed and ageratum that you cited? FL native Lantana is practically nonexistent.

I have loads of native Lantana on my farm and yearly I get another half dozen or more from the birds spreading the seeds.

google Fl. native plants and you should get lots of ideas.

> "native Lantana on my farm"

Species, please.

Looks like I have the common invasive one Lantana Camera:

http://plants.ifas.ufl.edu/plant-directory/lantana-camara/

to create a butterfly garden, you will have many more butterflies if you include host plants as well as nectar plants. There is likely a native plant nursery near you, find one through the Florida Native Plant Society. The proprietor of your locaal native nursery should be a good resource for you.