Polygonaceae (Polygonum)
Polygonum (paronychia)
Polygonaceae
Buckwheat
Polygonum
paronychia
beach knotweed, black knotweed
POPA7
Central Oregon Coast
San Luis Obispo County, CA north to Vancouver Island, BC. Found in sandy coastal habitats including dunes and scrub.
none
Seeds
Seed
Propagules (seeds, cutings, poles, etc.)
Deepot D40 (2.5" diam. x 10" deep)
6-8 months
large well-rooted plug
Seed ripens indeterminately and this species can be found in bloom in nearly all months of the year. Achenes were collected on the Central Oregon Coast in August, but the general collection window in this region begins as early as June and extends as late as October.
Dry plant material was threshed in a Westrup LA-H brush machine with solid mantle at low speed. Seed was separated from inert plant matter on a Clipper Office Tester using a 6 round top screen and 1/16 round bottom screen with air at medium-high setting. It is difficult to separate seed from all inert plant matter, especially broken leaf pieces. Further conditioning may be necessary depending on ultimate use of seed.
In controlled tests, germination was optimized with 8 weeks cold-moist stratification (71%). Germination did not improve significantly with scarification or longer periods of cold-moist stratification.
Half of the containers were filled with ProMix-HP+, a high porosity peat and perlite-based medium. The remaining half of containers were filled with a mix of 1 part washed river sand to 2 parts ProMix-HP+.
Plugs were well rooted and ready for transplant in 6+ months from emergence. Establishment from seed was 95% in ProMix-HP+ and 75% in the sand-HP mix. Large plugs were used in this effort because the project had goals other than plug production; smaller plugs would likely be successful and could be established quicker.
This species is slower to emerge and grow than many other coastal dune species, requiring up to 30 days to germinate.
Plugs were planted in a seed increase field in November in Willamette silt-loam soil in Corvallis, OR (very different than the native habitat soils). Plants grew slowly through the winter and then actively throughout the spring and summer. Plants received no supplemental water. Plants bloomed abundantly and seed was harvested in November by cutting all branches back to the main stem, leaving about 6" of the main stem in the ground. The following year, plants regrew actively and were reharvested.
Silvernail, Ian. 2023. Propagation protocol for production of Propagules (seeds, cutings, poles, etc.) Polygonum paronychia Seeds Deepot D40 (2.5" diam. x 10" deep); USDA NRCS - Corvallis Plant Materials Center Corvallis, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/05/21). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.