We have had good luck growing Asclepias Incarnata, or Rose Milkweed, also known as Swamp Milkweed. It is not native to Oregon but does very well here west of the mountains. It tolerates shade or sun so would do well for people with shady gardens. It grows about 4 feet tall and has clusters of rosy pink flowers. Said to be deer resistant.
I have also had good luck with Asclepias Tuberosa. A much smaller plant with bright tangerine colored flowers.
Asclepias Speciosa, or Showy Milkweed grows well east of the mountains but not so well in our yard. Other people might have better luck with it.
Prairie Moon Nursery carries these and other varieties, online.
Eric Griswold lives on Johnson Road