Has been in a pot for some years, large, healthy leaves. Has full sun, fertilizer in spring (usually osmacote). I also have a plant in the shade, equally large, strappy leaves.
Why Does My Blood Lily Not Flower?
When plants don't flower, the two most likely reasons are not enough sun, and too much nitrogen. Doing some research on these spectacular plants, I see recommendations for open potting medium similar to orchids; partial (50%) sun, and keeping them pot-bound. This article might give you some ideas: https://www.gardeningknowhow.com/ornamental/bulbs/blood-lily/how-to-grow-african-blood-lily.htm