Oregon's abundant lakes--including Crater Lake, the deepest in the United States--rivers, streams and wetlands are home to hundreds of aquatic plant species. Majestic trees, shy herbs, lush grasses and showy shrubs, all thrive in the moist soils near the Beaver State's waters. Many of these plants will transition successfully to water and shade gardens in home landscapes.
Calamus (Acorus calamus), also called sweet flag, is a grass-like aquatic perennial, native to Oregon's pond borders. Standing up to 5 feet tall, it has narrow, upright green leaves and a double-edged stalk. Bruising any part of this plant releases a pleasantly sweet fragrance. From June to August, calamus' stalk has a club-shaped head covered with tiny, yellow-green flowers. Rising above them is a narrow green leaf--spathe--up to 12 inches long. Calamus, according to the Lady Bird Johnson Wildflower Center (LBJWC), grows partially in and partially out of water. Its sweet roots were once a candy ingredient. Plant calamus in a sunny to partly shady location with wet, acidic (pH below 7.0) soil.
Cigar tree (Catalpa bignonioides) is a member of the trumpet creeper family native to the southern coast of the United States. It has escaped cultivation and naturalized across the country. Today it grows wild along stream banks and in the wetlands of Oregon. Between 25 and 40 feet high and at least as wide, cigar tree has short branches with large, heart-shaped, pale-green leaves. In late spring and early summer, its twigs bear clusters of fragrant blooms. The showy, white, five-lobed flowers are up to 2 inches wide. Their throats have a pair of bright-yellow splotches as well as purple stripes, and smaller, purple and yellow spots. Cigar-like seedpods give the tree its name. Plant it, advises the LBJWC, in moist or wet soil, and partial shade.
White Marsh Marigold
A buttercup family perennial, white marsh marigold (Caltha leptosepala) thrives in bogs, wet mountain and foothills meadows, and along stream banks in more than half of Oregon's counties. No more than 1 foot high, it has basal clumps of wavy-edged, glossy-green leaves. Between May and August, according to the LBJWC, each of the plant's leafless stems produces from one to three white blooms. The flowers' dense, yellow stamens add to their appeal. Like the cigar tree, this plant prefers a partially shady location with moist to wet soil.