That is a Bumelia, or Chittamwood. It's native to much of the lower 2/3 of the nation. It can get quite large. The latin name is Sideroxylon lanuginosa.

We have some of these in our back 40, so I rarely see them, but they make large trees if they survive the wood borers. The flowers have a nice aroma, and the birds like the dark bluish berries that form. In our neighborhood, the old guy who taught me about the trees here on our propertly called it woolly buckthorn or gum tree. It is known by many different nicknames.

Oddly, one sprouted near our chicken coop too, likely planted by a bird, and we just saw it off at the ground about once a year. It slowly resprouts and sends out new shoots, but I can't let it grow there because it would block the walk-in door to the coop.

Out back where we have left them alone, the slowly form an ever-enlarging thicket over time. They aren't picky about soil (ours are in dense, red clay) and tolerate drought (2011 didn't even kill them).

Dawn

LOL, at Dawn, 2011 didn't even kill them! But on the other hand, everything that survived, should do ok, or maybe even thrive in Oklahoma.

Moni, obviously one very good thing came out of 2011. I learned what plants were really and truly drought-tolerant here in our area. Some plants that died surprised me (some oaks on dry ridges, and particularly prickly pear cacti) and some of the Mexican plum trees. Others surprised me by surviving (especially young persimmon trees that survived while older ones died). So, yes, 2011 now is the year by which I judge which plants are survivors and which ones aren't. It isn't much of a system, (grin) but it is the only one I've got.

Dawn