Gomphocarpus physocarpus, previously known as Asclepias physocarpus (it's name was changed in 2001), is an undershrub Milkweed perennial that can grow to over six feet! The plant blooms in warm months. It grows on roadside banks, at elevations of 2800 to 5000 feet above sea level. The plant prefers moderate moisture, as well as sandy and well-drained soil and full sun.

The flowers are small, with white hoods and about 1 cm across. The follicle is a pale green, and in shape an inflated spheroid. It is covered with rough hairs. It reaches three inches in diameter. The leaves are light green, linear to lanceolate and 3 to 4 inches long, 1.2 cm broad. The brown seeds have silky tufts.

Seeds are rare and difficult to find.

Type: Hardy perennial

Height: Up to 6 feet!

Location: Sun or part sun

Hardiness zones: 8-10

Seeds per pack: 10

Note: Ornamental use only. These seeds and/or plants are poisonous.

Germination: Start these seeds right away to preserve viability, no matter the time of year. Sow the seeds just under the surface of a sterile seed-start mix, and water in. Then cover them with plastic and place in a fridge for 5-6 weeks. Be sure they stay moist. After the cold stratification period they are then brought back to room temperature for them to germinate. Germination is generally within 60 days after the warming period, though they could take a few months. If possible, the best location for sowing in March, April and May, is in cold frame or a cold greenhouse where they will receive the cold period and fluctuating temperatures naturally.