Propagating your ornamental sweet potato vine to expand your plant collection, or to overwinter your plant to grow again next year is really easy. You can take cuttings of your ornamental sweet potato vines and root the cutting in water. But using a simple layering method or (tip layering) is just as easy and saves you the repotting step of rooting in water because the vine will root in a pot with potting soil as it grows.
I find layering propagation of ornamental sweet potato vines is faster when you select the tip of a growing vine like in Figure 1. Take the tip of your sweet potato vine and begin to wrap it along the inside of a pot with your favorite potting soil as seen in Figure 2 and wind the vine making sure to bury the vine with potting soil as you go around. You can secure the vine in place as you wind around your pot by using some U-shaped pins like in Figure 3. This will help keep the vine below the soil level where it is dark and moist; encouraging root to form from the leaf nodes along the vine.
If you don't have any U-shaped pins you can quickly MacGyver some out of a piece of wire from your tool shed or from a paperclip as demonstrated in the image above.
After a couple of weeks your ornamental sweet potato vine will be fully rooted inside the pot you layered it. As your vine is rooting make sure to keep it moist and don't allow the soil to dry out. The moist soil will encourage your vine to root and the roots drying out at this stage could keep your vine from establishing. Once you're happy with the root formation inside the pot and you notice lots of new growth you can separate your vine from the parent plant but cutting somewhere along the line illustrated above in the picture of the ornamental sweet potato vine in my garden.
How to Root Cuttings of Ornamental Sweet Potato Vines
Whether you choose to root your ornamental sweet potato vines in water or decide to propagate your vine by using a layering technique is a matter of preference. Sweet potato vines are easy to root whether you want to make more to plant in your garden, or you're looking to overwinter some indoors to save you some money the following growing season.