Help me identify my plant...

I have this plant growing out of what I thought to be a pot full of dirt only. Well it is now over 6 feet tall and just a few weeks ago began getting yellow flowers on top. It does seem to like the Las Vegas heat as I had to bring it inside during the winter because it began to wilt in the cold, but when it gets over 100 degrees it seems to have a growth spurt. Sometimes up to 2 or 3 inches in one day!

Any help is appreciated.

 

Nicotiana of some sort. Maybe N. glauca.

http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=38821&highlight=NICOTIANA

 

Yep, Nicotiana glauca. Often considered a weed, though the flowers are good for hummingbirds.

 

Thank you all very much. We had several people here in Vegas take a look at it with no luck. Some mentioned it might be some sort of weed, but after it grew to over 6 feet we were not sure.
Again, Thanks A Million

 

If you think 6 feet is impressive, let it go. Here in Ecuador, those form up into 10-12 foot trees.