

Striped Knotweed Polygonum striatulum
Striped Knotweed is an annual shrub native to the lower 48 states.
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 6 derived from its U.S. range
- Lifespan
- Annual
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~58 caterpillar species
Polygonum supports ~58 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a strong genus.
Recorded feeding on Polygonum in North America, including:
+ 8 more species → ↑ show fewer
How we know this (1) Methods & honest limits
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
Sources for this entry (14) Open & cited
Cite this page Open data, please attribute
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