weeds or keepers?

These 3 things are growing wild around and on our property. Does anybody know what they are? The dragonflies love the one on the left, which is growing in our bog-to-be. The one on the right is also in our bog-to-be. The middle one is from a plant that has sprung up on the empty lot next to ours and is alread 6 feet tall. (We're only a couple of blocks off Aransas Bay, so these are salt-tolerant plants. We had our lot filled, and the bog is an area that we left as is on the salt flats.
I'll post more pix.

Another photo. The taller grass kind of splays out. It's surrounded by the plant that is on the right in the first photo I posted. This is our bog.

A picture of the plant whose branch is in the middle of the first picture. Sorry it's not a very good picture.

And a picture of the other weed - the one standing on its own near the middle of the picture.
Any ideas would be most appreciated.

Decklife, the plant in the center of your first picture is
Bagpod, Sesbania herbeceae, http://davesgarden.com/guides/pf/go/68448
an annual Texas native plant, the other two I don't know.
Josephine.

The grass in the last photo is of Distichlis spicata var stricta, inland saltgrass. The other grass is harder to ID because there are a number of grasses that look like it. You need to need to acertain whether it grows from a common clump (a bunch grass) or whether it is rhizomatous (spreads by rhizomes). You'll need a clear photo of the whole plant, one of the the entire inflorescence, a close-up of a spikelet ( smaller units that make up the inflorescence) and the seeds. The best bet would be to remove a smaller plant, one that has all the components, bag it to keep it fresh and to get it IDed by your local Cooperative Extension agent.
http://aransas-tx.tamu.edu/

Thank you so much for the i.d.'s and the advice on what to give the extension agent to make the other i.d. Much appreciated!