Hi, my autumn splendor hasn't starting growing too much yet so I can't provide info for you. But I hope it grows horizontally!! If you have photos would love to see them...

Some minis do start out sprawling and seeming to grow horizontally. However, once they get established the canes do go up instead of out. I have two Autumn Splendors and they both grow fairly erect and are topping three feet currently. You will love it once it gets established. Give it a year.

Thanks for the inputs. Sorry no photos. 'Sprawling' is a good word for the abundant tangled growth. The new canes are actually resting on the ground with buds pointing up like mini bulbs on a fallen chain of Christmas tree lights. I hope a new stage of erect growth kicks in soon. I don't see how these horizontal canes will ever lift off the ground.