Douglas' Knotweed
Polygonum douglasii
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Polygonaceae
- Genus:
- Polygonum
- Species:
- Polygonum douglasii
Growth Characteristics
- Life Cycle:
- Annual
- Growth Habit:
- Forb/herb
- Height:
- 2-3 ft
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Medium
- Bloom Months:
- jun, jul, aug, sep, oct
- Bloom Colors:
- White, Pink, Green
Native Range
United States: Arizona, California, Colorado, Iowa, Idaho, Maryland, Maine, Michigan, Minnesota, Montana, North Dakota, Nebraska, New Hampshire, New Mexico, Nevada, New York, Oregon, South Dakota, Utah, Vermont, Washington, Wyoming, Canada: Alberta, British Columbia, Manitoba, Ontario, Quebec, Saskatchewan
Host Plant for Caterpillars
Epidemia helloides, Epidemia mariposa, Epidemia nivalis
Soil Requirements
- Soil Type:
- sandy, well-drained, nutrient-poor soil
- pH:
- 5.5 - 7.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- Commonly found in disturbed areas and open habitats.
Germination Information
Pre-treatment: Seeds are placed in cold moist stratification for 60 days.
Establishment: P. douglasii is found from British Columbia to Colorado. There are 7 recognized botanical varieties. Germination was greater in light than on dark.
Source: npn.rngr.net