Water Knotweed
Persicaria amphibia
- Native to:
- Afghanistan, Albania, Algeria, Austria, Baltic States, Belarus, Belgium, Bulgaria, Canada, China, Corse, Czechia-Slovakia, Denmark, Ethiopia, Finland, Føroyar, France, Germany, Greece, Hungary, Iceland, India, Iran, Iraq, Ireland, Italy, Japan, Kazakhstan, Kenya, Kirgizstan, Korea, Krym, Kuril Is., Labrador, Lesotho, Morocco, Nepal, Netherlands, North Caucasus, Norway, NW. Balkan Pen., Pakistan, Poland, Portugal, Prince Edward I., Romania, Russia, Sardegna, Saudi Arabia, Sicilia, South Africa, Spain, Sweden, Switzerland, Tadzhikistan, Transcaucasus, Tunisia, Türkiye, Türkiye-in-Europe, Turkmenistan, Ukraine, United States, Uzbekistan, Yemen
Svdmolen
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Polygonaceae
- Genus:
- Persicaria
- Species:
- Persicaria amphibia
- USDA Symbol:
- POAM8
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 100 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Low
- Bloom Months:
- jun,jul,aug,sep
- Bloom Colors:
- pink, white
Wildlife Benefits
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Host Plant for Caterpillars
Salt Marsh Moth (Estigmene acrea), Epidemia helloides, Hyllolycaena hyllus
Reported Fauna Sightings
Bees: American bumble bee (Bombus pensylvanicus), Brown-belted bumble bee (Bombus griseocollis), Common eastern (Bombus impatiens)
Garden & Ecology Notes
- Wildlife Value:
- waterfowl, songbirds, small mammals
Soil Requirements
- Soil Type:
- rich, organic, moisture-retentive soil
- pH:
- 5.5 - 7.5 (slightly acidic to neutral)
- Drainage:
- tolerates poor drainage
- Moisture:
- consistently moist
- Notes:
- Commonly found in wetlands and along water bodies
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–90 days
- Germination Time:
- 14–60 days
- Notes:
- Seeds germinate best when kept moist and may have variable germination rates. Light may improve germination.
The above propagation data sourced from Claude AI
Pre-treatment: Seeds were cold stratified for 210 days for optimal germination. A shorter stratification period of 147 days may also be used.
Establishment: There is a variation in the pre-treatment protocol regarding the duration of cold stratification. Longer stratification period may result in better germination.
Source: npn.rngr.net