I'm not sure, there are several species that I have heard go to 6 feet. It you grow them in the shade many will reach that. I don't grow mine that way and the tallest that I have at this time is 4ft+ I don't bother to measure. It will depend on their care. They all start to look alike to me if grown that way and fall over, they need sun to make the grow straight up and beautiful. Just my opinion. Over head sun will help them grow straight up. Good morning, Norma

Thank you. I was wondering if it was cultural or cultivar issue.

Here's S. stuckyi that appears to be about 9 feet tall.
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Here's another pic I found on the web of S. stuckyi.

OOOOH! Thanks for taking the time to post the pictures for me Brandon. I am impressed. If only those babies were winter hardy. I had hoped for maybe 5 feet or so, but nine plus feet would be hard to accomodate on the fireplace hearth over winter- LOL. Still I keep going back to your pictures and saying WOW, if only............

I've never seen then that tall, no reported that tall, WOW thanks for the pictures, a real eye opener. Those are not babies, ";o Norma

I have also found out that my pots need to be larger for my plants to obtain that height. But I don't have the room to pot them up another time unless I can hang them on the walls or the roof in hanging baskets in the greenhouse, but then the weight will pull my greenhouse down. Norma