Common name:  Western skunk cabbage, swamp lantern, ʹqilť (southern Lushootseed)

Family:  Araceae (Arum family)

Location:  Along wooded creeks and wet areas in the Arboretum – Rhododendron Glen, portions of Arboretum Creek.  In Yesler Swamp at CUH.

Origin:  Lysichiton americanus is native to the Pacific Northwest, from southeast Alaska through BC and into northwest California.  Native to cooler areas of Pacific Northwest, it reaches into isolated populations from northeast Washington into western Montana, but it found in abundance west of the Cascades.  It is closely related to the east Asian species, Lysichiton camtschatcensis, which has white flowers rather than yellow and is native to northern Japan to the Kamchatka peninsula in the Russian far east.  The two can species hybridize when planted in close proximity and are sometimes seen in ornamental plantings.

Western skunk cabbage is native from sea level to mid elevations, always located in wet areas such as creek channels, swamps, bog margins and winter wet areas.

Odor can vary, but to my mind is usually quite mild.  It is not nearly as strong as the eastern skunk cabbage, which is a different species entirely (Symplocarpus foetidus).  It is also a member of the Arum family, with a similar looking though smaller flower—but it is much smaller and has different flower coloration ranging from greenish-yellow giving way to darker blotching of burgundy and purple.

Height and spread:  In the wild, western skunk cabbage can easily reach 3’ tall and wide.  In cultivation it can reach similar sizes in sites with soils rich in organic matter and that remain consistently wet.  It is very happy in the wet woodland and along watercourse margins, even with areas with early season sun before the deciduous tree and shrub canopy above leafs out.   There are many good patches in Seattle’s wilder wet ravines and shaded wetlands that often contain hundreds of plants.  Prevalent in wilder areas regionally, its bright color and large flowers make it easy to view from vehicles along early spring roadways in western Washington.  There is no other flowering sight to compare with skunk cabbage in early spring.

Flowers are produced within a flowering stalk called a spadix, which is located within a bright yellow, hooded bract called a spathe.  The spathe can reach 12 to 20” tall and appears before the leaves fully emerge.  Leaves are produced on short stalks but are large and broadly elliptical as they mature.  They arise from basal roesettes and are the largest of any native species.  Soon after the flowers first appear they rise and unfurl, reaching enormous sizes and giving rise to the “cabbage” part of its common name.

The plant is fully dormant in the winter months, with foliage collapsing and turning yellow by the end of autumn (or earlier on drier sites).  Plants grow from rhizomes (a modified underground plant stem), which can reach a foot or more down into the soil.   Once established in a suitable location they will come back every year and gain size in time.

Western skunk cabbage has been grown in the United Kingdom since at least 1901.  It has escaped cultivation in parts of the UK and Scandinavia, and since 2016 has been classified as an invasive species by the European Union.  Control can be very difficult when established.

It resents sunny and even moderately dry sites, and will not establish or grow in areas without consistent year-round water.

Hardiness:  Cold hardy to USDA Zone 5

Other information:  Stems and roots are eaten by elk and bears, but the plant contains calcium oxalate crystals and can cause intestinal irritation in humans with larger quantities being toxic if not prepared properly.  Different parts of the plant are used by indigenous people.  Leaves are used for food preparation and storage, and different parts of the plant are used for some medicinal treatments for burns and injuries.  Roots and young leaves are cooked and eaten as an emergency food source in small amounts.

Western skunk cabbage was often referred to as “swamp lantern” by early settlers, and it is not hard to see why.  Their blazing yellow flowers do seem to light up any setting in which they grow.

Lysichiton americanus is a sure harbinger of spring in the maritime Northwest.  Among the earliest native species to flower, its bright color, large size and local abundance are easy to spot and promise warmer days ahead after the long dark of winter.