Sauromatum venosum “Voodoo Lily”. One more caveat about aroid lilies, besides sometimes being stinky: a lot of them put out fruit clusters that turn bright red or orange when they ripen, which may clash with your color scheme. Just remember to cut down the spent flower heads before they get there, if it'll bother you.
Super heat tolerant. Low water needs. Fast multiplier. Seems to thrive in rocky soil. Green, really green all year round. A single bulb planted 2 years ago has now multiplied to 30 bulbs. Easy to transplant. They come in a multitude of colors. The Zephyranthes Candida in the photo are the variety that I have had the most luck with.