Transplanting Morning Glories

:( not thriving after transplant

I started drafting this post a few weeks ago because I was truly hoping the result would be my reporting that the experts were wrong, and that you truly CAN transplant morning glories.  Unfortunately, my scientific lab results (my back porch and front porch) have in fact proven to me that you can't transplant morning glories once they are at a certain point.I had read that in a few places (links below)

• PlantFiles: Detailed information on Morning Glory, Grannyvine Ipomoea tricolor 'Heavenly Blue' and 
• will morning glories transplant - Oklahoma Gardening Forum - GardenWeb 

but because I had success starting seeds and then placing them in flower beds after I was optimistic.   But a seed that was actually started in my hanging baskets, and then started to get out of control for that small space did not do well when I moved it into a flower pot on my back porch as you can see.  

I still have a few more that haven't failed me, as you can see by this small plant next to my hummingbird feeder.   My scientific "hypothesis", yet to be proven, is that if you plant them before they start to vine, they will be fine.  If you plant them after the vine has started to cling, then you are probably going not going to be happy with the result.

If you have done "data collection on transplanting morning glories, please share!