Sium latifolium, commonly known as great water-parsnip, is a perennial herb that thrives in the riparian zones, marshes, and wet meadows of Europe, Western Asia, and Siberia. It is often found along the margins of slow-moving water bodies such as rivers, streams, and lakeshores. This plant can reach up to 6.6 feet in height and features hollow, grooved stems. The foliage consists of large, pinnate leaves up to 12 inches long, with leaflets arranged in an opposite fashion. The leaves are borne on hollow petioles that clasp the stem at their bases, providing a distinctive appearance. Great water-parsnip blooms in the summer, producing small, white flowers arranged in compound umbels, which are moderately showy and attract various pollinators.

Great water-parsnip is valued for its ability to naturalize in wetland restoration projects and can be used in water gardens for its tall, striking foliage. It requires consistently moist to wet soil conditions and can even grow in shallow water, making it suitable for pond margins and bog gardens. It prefers full sun to partial shade. While it is not commonly grown in typical garden settings due to its size and habitat requirements, it can be an interesting addition to naturalistic plantings. Care should be taken as Sium latifolium can spread outside its native range, and gardeners should consult local regulations before planting.CC BY-SA 4.0