Papyrus (Cyperus papyrus) is native to the Nile Valley and subtropical Africa—not the United States. It cannot survive winters outside USDA Zones 9–11 (minimum ~20°F / -6°C).
Grown nationwide in pots, water gardens, conservatories. Overwinter indoors (bright light, wet feet, >50°F). Cultivars: 'King Tut' (dwarf, 4–5 ft), 'Prince Tut' (compact), 'Baby Tut' (2–3 ft). Popular in Proven Winners lineup.
In Zones 9–11, papyrus can escape cultivation and invade wetlands, clogging waterways, displacing natives (e.g., Florida's Cyperus.haspan, Cladium). Never release into natural water bodies. Check state invasive lists (FL: Category II; TX: watch list; CA: not listed but caution).
Ancient Egyptians cultivated papyrus as a monoculture for 3,000+ years—paper, rope, sandals, boats, food (pith), fuel. The US has no equivalent tradition; it's purely ornamental here.
Bottom line: Not native, not naturalized broadly, but cultivable in warm zones or as a container plant anywhere. Respect its invasive potential.