© Marilynn Miller, some rights reserved (CC-BY) · iNaturalist
Decodon spp.
Overview
Decodon spp. is a genus in the loosestrife family (Lythraceae) with a single species, D. verticillatus, native to wetlands of eastern and central North America. It is a deciduous, woody-based perennial that produces long, arching stems 3-8 feet (0.9-2.4 m) long, which bend down to the water and root where their tips touch, forming spreading colonies along shorelines. The lance-shaped leaves, 2-5 inches (5-13 cm) long, are arranged in whorls or opposite pairs and turn red to orange in autumn. From midsummer into early autumn, clusters of magenta-pink trumpet-shaped flowers about 0.5 inch (12 mm) wide open in the upper leaf axils. The flowers occur in three style-and-stamen forms across different plants, an arrangement that promotes cross-pollination by bees. Stems standing in water develop thick, spongy, pale corky tissue at the base that aids flotation and oxygen movement to submerged parts. The plant grows in standing or slow-moving fresh water at pond and marsh margins and spreads readily, which can crowd small water features. It dies back to the rootstock each winter and is hardy through cold zones. Wetland plantings use it for shoreline stabilisation and pollinator habitat.
Native Range
Native to eastern and central North America, from Nova Scotia and Ontario south to Florida and Louisiana, in marshes, swamps, pond edges, and other freshwater wetlands.Suggested Uses
Used at pond and lake margins, in rain gardens, bog gardens, and constructed wetlands for shoreline stabilisation and erosion control. The late flowers support bees and other pollinators, and the arching colonies shelter aquatic wildlife.How to Identify
Appearance
Size & Dimensions
Height3' - 8'
Width/Spread3' - 6'
Bloom Information
Detailed Descriptions
Foliage Description
green turning red to orange in autumnGrowing Conditions
Sun Requirements
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow in full sun to partial shade in constantly wet, acidic soil with a pH of 4.5-6.5, at the margins of ponds, bogs, and slow streams or in standing water up to about 12 inches (30 cm) deep. The roots need permanent moisture and do not tolerate drying out. Plants spread by tip-rooting stems and can form dense colonies, so confined water features may need the spreading stems thinned. It dies back in winter and regrows from the crown, hardy in USDA zones 3-9. No fertiliser is needed in fertile wetland soil. Propagation is easy from layered stem tips or division.Pruning
Old stems are cut back to the waterline or ground in late winter before new growth begins. Excess tip-rooting stems can be removed during the growing season to limit spread. Spent flowering stems can be left for winter structure and seed.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winterearly spring
Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons