In my opinion this is more of a collector’s item as the flowers are not real showy and are similar to verticillata which is a better flowering plant. Flowers are generally purple from early spring to summer but can be lighter colours.
The name refers to the Nile River where the plant originates.
Nilotica is very cold tolerant and likes average water.
I probably have one in a pot though I don’t look after them well as they are not so interesting.