Decodon verticillatus

Common Names

Swamp Loosestrife, Water Willow, Water-Willow, Waterwillow

Summary

Swamp Loosestrife, also called Water Willow, is a native wetland perennial of eastern North America in the Lythraceae family. It grows as a marginal aquatic plant in swamps, marshes, and lake or pond edges, with arching stems reaching about 2–4 feet in height, opposite or whorled lance-shaped leaves, and clusters of pink to purple bell-shaped flowers in the upper leaf axils from midsummer to early fall. In cultivation, this species favors wet sites with full sun to part shade and moist to wet soils along water edges, and it can spread rapidly to form dense mats; propagation occurs by seeds and clonal growth from stem tips that contact moist ground. It is used in waterside plantings, erosion control, and mass plantings, while providing wildlife benefits by attracting pollinators and offering habitat; it is hardy in USDA zones 3–9.

Lifecycle

Perennial

Height

2-8 feet

Spread

6-8 feet

Hardiness Zones

Zones 3-9

Sunlight Requirements

Ideally full sun to partial shade.

Soil Type

Wet, mucky, peat-rich soil

Soil Drainage

Wet, poorly drained soils (saturated wetlands and edges of standing water such as swamps, marshes, lakeshores)

Soil pH

Acidic to neutral soil pH, Tolerates all pH levels

Bloom Color

Pink

Bloom Time

Summer to Fall

Foliage Color

Green

Fall Foliage Color

Red, Orange

Leaf Lifecycle

Deciduous

Growth Rate

Fast growing, rapid spread

Seasons of Interest

Summer and Fall

Propagation Methods

Seeds, Layering, Cuttings, Division

Attracts Wildlife

Attracts bees, butterflies, other pollinators, and birds