There are a lot of xeric Mexican sages you can plant, including Salvia melissodora and S. keerli, which will draw your butterflies and other insect wings (bumblebees, even wasps). I'd recommend any of the 3 or 4 available forms of Salvia regla, and many of the S. microphylla and S. greggii forms and hybrids (this includes x jamensis). I'd also explore their relatives like S. chamaedryoides, muelleri, lycioides (especially greggii hybrids), and coahuilensis. You must have fire ants. Dou you also have pine voles? If not, there are a bunch of tuberous sages that should work, including many of the guaraniticas, involucratas (including puberulas) Try Salvia disjuncta Strybing form, S. reptans, west Texas form, S. roemeriana, S. penstemonoides, and many of the S. leucanthas and S. mexicanas. S. vanhouttei forms like Dancing Flames are probably not hardy, but are good bloomers. The broad-leafed ones should go into the shady areas. If you have any dampish spots there (relatively speaking), there are a few others like S. miniata and the S. blepharophyllas.

Here are pictures of the two carolina jessamines I have. They were both planted in 2004 when they were about a foot tall. The first one is now growing above the 4 ft tall fence. The second one is taller looking but that's because a lot of it is growing up rather than out. Keep in mind that in the past I haven't fertilized them or done anything else. I've left them to their own devices. I don't personally consider these to be fast growing plants but that could be because of where they're planted or the neglect. But anyway, the pics might help you. :)

For me leaf shape and arrangement of shrub not like that one. Also does it grow in Texas? But I have nothing else to suggest.

Ksus, can I ask why you want them from "native" trees? If that is really what you are looking for, they shouldn't be that hard to find. Pawpaws are actually very common in woods and forests around the area. Finding the fruit may be a little bit more difficult because pawpaws growing in the shade produce MUCH LESS fruit than those growing in full sun AND animals love to eat the fruit (before you get a chance to find it). But, it is out there. I see pawpaw seeds in animal scat very frequently. Most of them are probably completely viable, if you are brave enough to dig in and collect them. Now, if you are wanting the seeds to grow trees for the edible fruit, I would strongly suggest that you consider buying grafted cultivars. The fruit is almost certain to be much better quality for eating. If you need info on growing the seeds, do a little Googling and then email me, through the message link on my GardenWeb profile, with any questions you can't find answers for. I will be happy to answer what I can.