I just buy the plants. I have the black and also the green and love them both. The chartreuse green go wild for me each year. I have a planter in front of my office that had both types along with deep purple wave petunias in it and I must admit, it really is magnificent. People stop and comment about it constantly.

Last year when I pulled the sweet potato vines from the whiskey barrels on my patio they had huge tubers attached. I wanted to keep them over the winter so I put them in the garage fridge thinking they would be safe there....hubby tossed them. I wanted to see if they would grow this year.

Think I read somewhere that the sweet potatoes in the grocery stores are treated so as not to sprout. This is the first year I've tried them and would be tempted to simply purchase the plants again next spring. I have the dark maroon (black?) and some light green with dark green speckles. I was surprised to see the maroon start blooming - very pretty lavender flowers. Petunia like, but petunias and potatoes are in the same plant family.

The grocery store sweet potatoes may be treated, but if you keep them long enough, they will sprout. I realized just today that some I have had for a few weeks are sprouting, and really healthy sprouts. I think I'll put them in a planter I just had to dismantle - plants were too large. If you keep the tubers from your vines overwinter in peat moss or the like, you can re-plant them. It worked for me for about 3 years, then I put them in the ground and couldn't be bothered.