There are many species of Morning Glories that can be true perennials (e.g.,Ipomoea albivenia, Ipomoea pandurata,Ipomoea platensis,Ipomoea leptophylla etc.,) in that the roots will survive for many years,but the perennial species that is most often grown is
Ipomoea indica...

You can do traffic control on the above ground parts as you see fit,but Ipomoea indica does not spread by underground rhizomes,although it does tend to root where the above ground stems make contact with damp soil...

The roots of Ipomoea indica are NOT very cold hardy and unless measures are taken to categorically protect the roots from freezing temperatures by a mulch...the freezing temperatures will keep the roots in check and will often kill off the roots entirely...bring some roots indoors for overwintering or overwinter some fresh rooted cutting...

Hope that helps...

Ron

Here is a link that might be useful: Ipomoea indica in the PlantFiles

I have ipomoea indica in my garden. It is not hard to contol. Just keep the runners in check. It does not spread underground.
Patsy

Thank you, Ron. I was afraid it was like the orange trumpet vines. We are still fighting the suckers on it! Sounds like I can control this as long as I stay on top of it.:-)

In 7b, you're more likely to have to 'stay on top of' keeping I. indica alive over winter than keeping it in bounds. Do mulch it heavily, and do take in a few starts in case winter gets your parent plant. My mom lives in 7b, and hers comes back sometimes. I live in 8a, and mine *usually* comes back, but I always overwinter some indoors just in case one of us loses our main plant.

I have a question about my perennial morning glory. It is four years old and covers a pergola by summers end. I always cut it down to the ground and clean the old vines off of the pergola sometime in the late winter. Do I need to do this? Do the new leaves and flowers come back on the old vine or just start anew?
Thanks for any input!

suitepea - The leaves can grow from whatever stem parts remain alive...

My thoughts are that it depends on how the old foliage and stems are looking...if the leaves and stems seem to be staying alive and you like the way they look, then you might try keeping them to see how that works out...or just removing whatever upper parts might be looking raggedy..