// SPECIES PROFILE · ANNUAL · NATIVE

Box knotweed

Polygonum buxiforme

Box knotweed (Polygonum buxiforme) is a annual in the — family. Native range includes AR, KS, MO, OK. Hardy in zones 1a–10b. Mature size 29"–6'. Blooms Jul–Nov.

// QUICK FACTS

Family: —
Group: annual
Native range: Native to 36 U.S. states, including AK, AR, AZ, CO, CT, DC…
USDA hardiness: Zones 1a–10b
Mature size: 29"–6'
Sun: —
Water: —
Bloom: Jul–Nov
Wildlife value: Pollinator and wildlife support
Ecological role: native species profile

Box knotweed (Polygonum buxiforme) — *Polygonum buxiforme* — Box knotweed. Photo by Dalgial via Wikimedia Commons (CC BY-SA 3.0).

Field Notes

[ growing · ecology · siting · care ]

Box knotweed (Polygonum buxiforme) is a annual in the — family. Native range includes AR, KS, MO, OK. Hardy in zones 1a–10b. Mature size 29"–6'. Blooms Jul–Nov.

Why it's on this list: native species profile. Native-range data from the Lady Bird Johnson Wildflower Center (NPIN), cross-checked against iNaturalist observations. Part of Rooted Revival's regional native plant catalog — true natives for Oklahoma, Arkansas, Missouri and Kansas.

Companion Planting

[ guild · polyculture · cross-layer pairings ]

In the same native range, box knotweed pairs naturally with: Common Sunflower (Helianthus annuus), Pitseed goosefoot (Chenopodium berlandieri), Pitseed goosefoot (Chenopodium berlandieri var. boscianum), Bush's goosefoot (Chenopodium berlandieri var. bushianum).