Fertile, moist but well-drained soil. Tags sometimes recommend misting when hot, but it may not be good to get them wet in the evening, which can lead to disease problems. Shade to a little sun. What the tags call blue often looks closer to purple.
Try to plant in a location that enjoys dappled sun and remember to water often. Keep in mind when planting that Winston Churchill is thought of as tender, so remember to wait until your soil is warm and the night time temperature is well above freezing before moving outside.