I bought one in a one gallon pot about 6 years ago and it's about 6 or 7 feet now.

They grow fairly fast in my with limey, caliche, thin soil. I'd say about 4 to 5 years. Remember as with most things the first year they sleep, second year they creep, third year they leap so don't give up if the going seems slow at first.

Thank you both for your insights. It gives me a good idea of what to expect with these!

I have one that came up from seed in the spring of 08. It is now close to 4 ft.
I think "slow growers" refers to in the wild. I was just thinking a couple days ago about how fast that seedling grew to it's current size.

I had a small rooted plant in a 4 inch pot planted January 2011. It finally made it to about 2 ft tall. I'm hoping for the leap next year. Was told that they grow faster if you get some soil from under a mature one. Got a scoop from under a much bigger one at the botanical gardens in spring 2012. Maybe that didn't help much....impatiently yours....c

Mine here in DFW is still creeping after 3 years. And last year it got some sort of bug on it that ate all its new growth. I want it to look like the one at the arboretum, but it's only about 2.5 ft tall. :-(

BTW, if you want to plant from seed, gather the seeds while the pod is still soft, but the bean is beginning to turn red.

I have two that came from seedlings from my parents' yard 6 years ago. I kept them in pots for 2-3 years then planted them in the yard. They're now approaching 6'...but they're in unimproved Dallas clay gumbo and partly underneath a tree. If I could go back, I'd plant them a few feet further away from the tree. I haven't really fed them, just added mulch around the base of the bushes a couple times a year. They do get regular water, courtesy of my neighbor's sprinkler system. :)

I am considering adding a couple to the opposite fence-line, where I want to replace the current red-tip photinia hedge.