About Sium suave Walter
Sium suave (water parsnip) has leaves whose shape and size depend on its growing environment. On moist ground, it forms basal rosette leaves around 3.8 cm long; in shallow water, it grows clusters of aquatic leaves. Once its leaves are fully formed, this flowering plant can reach up to 3 meters tall, with stems up to 5 cm in diameter. Water parsnip stems are light green, glabrous, have longitudinal veins, and bear few branches. Leaves growing along the stems are alternate and odd-pinnate. Water parsnip flowers are perfect, meaning they have both male and female parts, and the species is self-fertile. The flowers form umbellule inflorescences that hold 10-20 small white flowers each; these flowers are around 3.2 mm across, with 5 petals that may sometimes be unequal in size and are somewhat heart-shaped. Flower pedicels are 3–5 mm long, and the fruit is ovoid. The fruit is dry and does not split open when ripe. Sium suave grows in wetland habitats, both sandy and non-sandy. These habitats include wet prairies, seep bottoms, low areas along springs, soggy thickets, swamps, pond borders and shallow pond water, marshes, and ditches. It is native to both North America and Asia, occurring in Canada, the United States, Japan, the Russian Federation, South Korea, and China. Extreme caution must be taken when using this plant for food, because it strongly resembles the very poisonous Cicuta maculata (spotted water hem-lock). Edible parts of Sium suave are the root, collected in spring and fall, which can be eaten raw or cooked and has a nutty flavor. Its leaves are also sometimes used in condiments such as relish. Crushed water parsnip roots have additionally been used as an analgesic, a pain reliever, for broken limbs. For cultivation, water parsnip should be grown in wet mucky soil or sand, or in standing water up to one and a half inches deep. It also prefers partial to full sun. Seeds should be sown in a cold frame from late winter to early spring. Sium suave flowers from July to August, and its seeds ripen from September to October. It has been found to accumulate arsenic and heavy metals near abandoned mine tailings in South Korea. When additional NO3-N is added to the soil, water parsnip shows increased production.
