16 August 2015

Balloon Milkweed is Asclepias physocarpa

Balloon Milkweed plants
The balloon milkweed seeds I planted last winter in the garden shed have yielded large plants that
will feed lots of monarch butterfly caterpillars this fall.

Asclepias physocarpa was so easy to start from seed that we were able to donate a flat of plants to Muskogee's butterfly house, Papilion.

The seeds are available to purchase but ours were given to us by our gardening friend, Jerry Gustafson.

Balloon Milkweed flower clusters

The flowers are unique in that they hang in little clusters from those large-leafed plants, making a dainty show when compared with how rough the leaves are.

Sometimes the plant is called Gomphrocarpus physocarpus. It is native to South Africa so in the US it is perennial only as cold as zone 8 or 9. Definitely an annual here in Zone 7. Kathy Coburn the director of Papilion said that they get volunteer plants in the spring from the previous year's seed fall.

Collect your seed balls in the fall to plant them late winter in a warmed environment. They need no cold stratification of course since they are from hot zones.
Asclepias physocarpa flowers

Just distribute the seeds on damp, sterile potting mix and press them into the soil surface. I sprinkled the top with a little sand or vermiculite to keep the damping off virus away.

Unlike tropical milkweed, Asclepias tuberosa that takes FOREVER to germinate, this variety takes only two weeks.


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