There's no rule saying you can't mix vegetables and ornamentals in the same garden. Furthermore, some gardeners line out ornamentals in the vegetable garden while they bulk up or until space becomes available elsewhere. Providing each has sufficient space and ornamentals do not interfere with cultivation and harvesting there is no problem.

I've sent the picture to a bunch of plant experts. Do you have the nursery name where you purchased it? Perhaps the owner would know more than the clerk. Where in Florida, if I may ask. The people to whom I've sent the photos are well known experts and curators at arboreta. Some work in Florida.

I would expect it to be some sort of cassia or senna, of which there are a number of species native to that area. btw, most photo hosting websites are completely innocuous and safe to open. Unless they expect you to pay for that service.......... :-) But are now unnecessary with the photo posting opportunities here. And it is much easier (and faster) for readers to have the photos embedded in the post.

Might just be neglect/lack of water...? It's been very, very dry here. March is usually like that. Judging from those photos, all the plants there are looking sad.