Ipomoea 'Lime' is not currently on the market, but it is being tested at our very own UT Trial Gardens and Greenhouses. In class or simply walking through the garden, you may notice this chartreuse sweet potato vine completely dominating the area in which it was planted (see left photo). In the area your group probably saw during class, this test variety of Ipomoea 'Lime' had grown over a mass planting of Geraniums, and into a small conifer and small Japanese Maple. In the photographs below, John - a volunteer at the UT Gardens - and I are attempting to control an area it has been planted by the entrance (see middle photo). Originally, three containers of Ipomoea 'Lime' were planted to fill in some blank space. Over time, it grew over a small planting of Coleus and into a Hydrangea, a small Japanese Maple, and a couple conifers. To quote John on how is best to control this plant: "There's not use being delicate with it and clipping it back nice. It'll be back just as bad by the end of the week," he exaggerated for effect, "so the what you want to do is just cut it way back."
Also, in the last two pictures is an actual sweet potato which we dug up in the process. Actually, before we began we were walking through and it had grown up above the surface several inches! It is roughly the size of a human head. CAUTION: Do not eat the sweet potatoes off an ornamental sweet potato vine, as they may not be suitable for human consumption. Check before eating. Additionally, sometimes regular sweet potatoes may also be planted for ornamental purposes.
In conclusion, if you need to temporarily fill up an area in the landscape quickly, this variety and several others are excellent choices for the job (since 'Lime' is not yet on the market, try 'Marguerite'. It is incredibly popular so you'll be able to find it basically anywhere). Just remember if something else is planted nearby, you may need to come by occasionally and cut away the sweet potato vine.
on variety - pers comm Beth Willis 16 September 2008
on controlling and edibility - pers comm John 16 September 2008