# Interior Butterfly Weed

*Asclepias tuberosa subsp. interior* Woodson

The butterfly weed of the interior, and the one most people grow. It is the commonest subspecies west of the Appalachians and the source of most nursery stock.

## How to tell it apart

Leaf bases are blunt, squared off or heart-shaped where they meet the stalk, and the leaves are narrower. Plants are 30 to 90 cm.

## Where it grows

By far the most widespread of the three, running from Ontario and Quebec south to the Gulf and west into Arizona, New Mexico and Utah, with scattered populations reaching the Atlantic coast. Orange and yellow flowers predominate in the western states, which is where the yellow seed strains sold as cultivars come from. It is rare enough in Quebec to be of conservation concern there.

States: AL, AR, AZ, CO, CT, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NE, NH, NJ, NM, NY, OH, OK, PA, SC, SD, TN, TX, UT, VA, VT, WI, WV

## Other names

Asclepias tuberosa var. interior; Asclepias tuberosa subsp. terminalis

Source: Flora of North America vol. 14 (2023).