>>>Can I take the flowers, dry
them up, and use them in a sachet, or do one of those home essential oil
I dunno. Try it and find out. It works with roses. I believe packing a
little salt in alternate layers with the petals is recommended to dry them
out faster and preserve them.
As to whether they are annual or perenniel depends upon which species you
found. There are 130 genera and 2,000 species in the mildweed family
(Asclepiadaceae) and about 200 species in genus Asclepias.
Most can be propogated by seeds or root division.
To respond via email remove the "X" from the address.