Agapanthus

We were given a white agapanthus some years ago. They always look so attractive, but I never have a great deal of success with them. This plant was in a border and after one year of flowering, it hasn't flowered since. It had got rather smothered by other plants and perhaps the soil was not rich enough for it. Anyway I have decided to try it in a pot to see if that makes any difference- there seems to be nothing to lose.