Rumex britannica.
Great Water Dock is a perennial wetland shrub in the buckwheat family that is native is to the upper midwestern United States where it can often be found growing in swamps, fens, and cattail marshes.
Plant grows to around 4 feet in height and produces numerous whorls of slender-stalked flowers that bloom from June through August, with distinctive seed heads forming late in the summer.
Copper Butterfly larvae and Ruby Tiger Moth larvae feed on the leaves and stems of the plant, while the seeds are an important food source for many different species of songbirds, as well as small mammals such as the muskrat.
Great Water Dock
Growth Chart
Hardiness Zones: 3 to 6 Light Requirement: Full sun Soil Type: Rich, wet Sow Depth: Surface Plant Spacing: 12 to 24 inches Germination Note: Cold stratification required Stratification Time: 30 days Bloom Time: June through August Growing Tips
Direct sow in late fall by scattering the seeds on moist to wet soil. For spring planting, mix seeds with moist sand and store in the refrigerator for 30 days (cold stratification) before direct sowing.
A Note on Cold Stratification
These seeds require cold, moist stratification. To naturally stratify the seeds, plant outdoors late fall on a weed-free site and allow seeds to overwinter.
To artificially stratify the seeds, place the seeds and a moist medium (such as a damp paper towel, coffee filter, sand, or vermiculite) in a labeled, sealed plastic bag and store in a refrigerator (33-40°F) for the amount of time noted on the growth chart before sowing.