'Blackie' is probably one of the most well known ornamental sweet potatoes for it's stellar garden performance and ease of culture.  This sweet potato is great at filling in large garden plots or containers with deep purple foliage.  The foliage is a wonderful accent to flowering plants.   
Mature Plant Size: 6"-10" Tall , 4' -6' Spread 
Bloom Time: From planting and up until frost. (if applicable)
Light Exposure: Full Sun or Partial Shade
Soil Type/pH: Well-drained/6.0-7.5 
Hardiness Degree: 34° Fahrenheit, 
Fertilizer: Incorporate an 1" of compost in the soil at planting or use your favorite granular fertilizer.  If growth is slow a liquid fertilizer can be used weekly until size is achieved.  Use an all purpose liquid fertilizer every two weeks in container plantings.
Containers Size: 4.5" Pot