This is my Latest Pictures of this Sweet Potato Vine where the pictures are more clear on the shoot development - especially the coloration of the tender foliage stem at the crown. The colors are strong and evident at these areas.
This particular one has a heart shaped leaf formation and a vibrant dark purple coloration on it's foliage. The tender shoot and new forming leaves does have that brilliant purple hue and slowly fades to green tones when turns matured. The bright lighting does play a role on this one, especially if it is exposed to long-day open sun the whole plant leaves coloration will be in total purple.
If in case, in a season in time where it is not exposed to the long sunlight,
eg: during rainy and cloudy days - this plant will be more in green tones.
Similarly it will turn more green when planted in semi-shaded areas.
I grow my sweet potato vine (Ipomoea batatas) solely for ornamental purpose.
They are trailing plant where they form roots at each node section
They do form edible tubers but I doubt it is enough for me or anyone to consume it.
Basically they are ideal for ground cover and does very well in open / direct sunlight area - doesn't fair well in shaded areas as they will turn faded green and loose the colors.