Shepherd’s purse – Yellow nutsedge
- Weeds: Shepherd’s-purse – Capsella bursa-pastoris
- Weeds: Smartweeds – Polygonum spp.
- Weeds: Sowthistle, annual and perennial – Sonchus oleraceus, Sonchus arvensis
- Weeds: Speedwells – Veronica spp.
- Weeds: Spurges (Prostrate spurges) – Chamaesyce spp. (Euphorbia spp.)
- Weeds: Stinging nettle – Urtica dioica
- Weeds: St. Johnswort, common (Goatweed, Klamathweed) – Hypericum perforatum
- Weeds: Tansy ragwort – Senecio jacobaea
- Weeds: Tumblemustard (Jim Hill mustard) – Sisymbrium altissimum
- Weeds: Velvetgrass (Common velvetgrass) – Holcus lanatus
- Weeds: Velvetleaf – Abutilon theophrasti
- Weeds: Water primrose – Ludwigia uruguayensis (L. hexapetala)
- Weeds: Waterhemlock, western – Cicuta douglasii
- Weeds: Wild carrot (Queen Anne’s lace) – Daucus carota
- Weeds: Yellow nutsedge – Cyperus esculentus