Common names: western ragweed

Scientific names: Ambrosia psilostachya (A. coronopifolia, A. lindheimeriana)

Seasons of significant use: spring, summer (for Ambrosia spp. complex)

Characteristics: Native, perennial, warm season forb to 3.5 feet (mostly less than 2.0 feet). Stems erect; leaves mostly alternate, simple (deeply pinnately lobed), and almost sessile; plants monoecious; staminate inflorescences racemiform; pistillate inflorescences in small axillary clusters below the staminate inflorescences. Flowers July-October.

Plant community type: Open areas.

Comments: In soils with low phosphorous, it can be encouraged with late winter fertilization using 2.5 to 3 times more phosphate than nitrogen followed by a late winter discing one time over. Late spring discing discourages it.

More Plant Photos and Descriptions:
Appendix C: Plants by Common Name
Appendix C: Plants by Scientific Name
Appendix C: Plants Listed by Family