I've tried plants from slips the last three years. I haven't seen a bloom. I have got a few small tubers. They have been grown in a large pot in full sun.

I have grown slips from sweet potatoes I bought. The plants are, IMHO, just a plain dull green, not the yellow or black ones you get at the nursery. Those you need to buy. Once you have them, some people either keep the tubers or take cuttings in the fall. My neighbour used to take cuttings in the fall and she always had wonderful planters.

I guess I will have to buy some.
Thank you that's very helpful information.

I find getting sprouts from grocery store sweet potatoes takes a very long tome, (10 weeks?). I think they are treated to prevent sprouting in order to lengthen their shelf life. Despite this, I have had them sprout and grow potatoes. For a good crop, they need lotsa sun and no water. They are not spectacular like the decorative varieties seen in hanging pots; but will grow in large planters as 'fillers'.

Place the sweet potatoes in jars of water on a heat mat and cover with spun-bonded polyester row cover. They will begin sprouting in 2-3 weeks.

I have had success growing them in the winter in water too, but it has to be kept very warm for them to sprout. Not cold temps or drafts at night in winter. I also start them in Nov/Dec to get sprouts for the spring. It does take a long time to start.

Thanks for the sprouting tips folks! I'll move mine to a heated spot right away.

Moved my sweet potatoes into a heated plastic "greenhouse", (Princess Auto shelves with a plastic cover) on March 9th. Got my first sprout April 20th, so about 6 weeks for initial success.

A few years ago I grew some planted directly in my garden. They were organic sweet potatoes tho which are less likely to be treated so more likely to sprout easily.