Sium suave
water parsnip
Overview
Sium suave is an aquatic to semi-aquatic perennial in the carrot family, growing 2–6 feet (0.6–1.8 m) tall from a cluster of fibrous roots in shallow water and wet ground. The erect stems are stout, hollow, and strongly ridged. The leaves are pinnately compound, 6–12 inches (15–30 cm) long, with 7 to 17 narrow, sharply toothed leaflets; submerged leaves are often more finely dissected than those above water. Small white flowers are borne in flat-topped compound umbels 1.5–3 inches (4–8 cm) wide at the stem tips in summer, followed by small ribbed fruits. It grows in marshes, pond and stream margins, ditches, and wet meadows across much of North America. The plant closely resembles the highly poisonous water hemlock, Cicuta spp. species, which share the same wet habitats. Parts of the plant contain compounds reported to be toxic to people and livestock, and the risk of confusion with water hemlock makes any wild collection hazardous. It spreads at the water's edge and does not grow in dry ground.
Native Range
Sium suave is native to North America and northeastern Asia, occurring across most of Canada and the United States in wetland habitats, and through parts of Siberia, China, Korea, and Japan.Suggested Uses
It is used in wetland restoration, pond and stream margins, and rain gardens with permanently wet soil. It grows at the water's edge in naturalized aquatic plantings.How to Identify
Appearance
Size & Dimensions
Height2' - 6'
Width/Spread1' - 3'
Bloom Information
Small white flowers open in flat compound umbels from June to September, peaking in midsummer. Bloom lasts several weeks. Ribbed seeds form afterward and ripen by late summer into autumn.
Detailed Descriptions
Foliage Description
bright greenGrowing Conditions
Sun Requirements
Requires 6-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight