'Mostly Ghostly' is a medium hosta which comes out of the ground white and eventually develops some flecks of green which multiply steadily until it appears somewhat "normal" by midsummer. This hosts needs mostly shade, or the white foliage will burn.
Grow in well drained soil in part shade to full shade to dappled light. Some varieties are listed as being suitable for full sun, but in our hot, dry climate, they all benefit from some mid-day sun protection. Ideally, provide a loamy soil, amended with organic material. Remove spent flower scapes after blooming to encourage more flowering and for a tidy appearance. In early spring, remove spent foliage, taking care to watch for new foliage emerging from the crown. Though not thought of as a "water-wise" plant, Hostas do remarkably well in dry part-shade to full-shade conditions, and are frequently the victim of over-watering, succumbing to crown or root rot.