Hellenia speciosa, also known as crepe ginger or spiral flag, is a tropical perennial herb native to South and Southeast Asia. Recognizable by its tall, unbranched stems and striking white, crepe-like flowers, it grows up to 4 meters tall from underground rhizomes. It has a long history of traditional medicinal use in its native range, treating ailments from earaches to dysentery, and its showy blooms make it a popular ornamental plant in tropical gardens worldwide. It thrives in partial to full shade and can adapt to a variety of soil conditions.

Despite its beauty, crepe ginger poses an invasion risk in tropical climates like Hawaiʻi. It spreads aggressively both by seed—which are dispersed by birds—and vegetatively through its persistent underground rhizomes. Once established, it can crowd out native understory plants. Its ability to naturalize, as seen in parts of Hawaiʻi and its invasive status in Sri Lanka, makes it a plant of concern. Landowners should avoid planting it and consider removing existing specimens to protect native ecosystems from this quietly spreading ornamental.