Starting Seeds indoors for a
Bounty of Blooms and Milkweed Seeds
One season, our Gomphocarpus physcocarpus (balloon plant milkweed) plants grew 8 feet tall and were our last milkweed plants to succumb to a harsh Minnesota winter….not too shabby for a milkweed variety that’s only cold hardy to USDA zone 8!
When growing annual butterfly plants, I follow some basic rules:
- Research plants to see if they are classified as invasive or a noxious weed for your region
- Learn what growing conditions your plant will need to thrive
- Research potential issues and make sure you’re willing and able to deal with them
- As the plants grow, keep a close eye on them and the surrounding plants for unexpected issues like disease or unwelcome pests
- If problems arise, take responsibility for your garden…even if that means pulling and discarding the plants
If Father Winter wipes out Asclepias species like tropical milkweed, giant milkweed, swan milkweed, balloon plant, etc…, sowing seeds outdoors each spring is not your best milkweed propagation option.
How Come? Most warm weather species don’t “get growing” until the temps trend tropical. If there’s a cool spring, your plants won’t have time to reach their full glory, or support monarchs, or produce seeds for future seasons!
Start Your Milkweed
Starting annual milkweed doesn’t require a lengthy cold stratification…or even a short one!
- Find Annual Milkweed Seeds
- Annual milkweed options are A. Curassavica (tropical milkweed), G. Fruticosus (swan milkweed), G. Physocarpus (balloon plant), T. caerulea (blue milkweed)
- C. Gigantea (Giant Milkweed) and C. Procera (Milkweed Tree) may not flower their first season in northern regions so these would need to be overwintered
- Fill up a small bowl with water for each milkweed species you are starting (labeling is recommended since seeds look similar)
- Put the seeds for each species in the appropriate bowl and soak them overnight. This will help soften the seed coat to increase the germination speed.
According to this seed germination database, you are supposed to soak asclepias seeds for a longer period. I’ve never done this, and overnight soaking has always given me a very high germination rate when starting seeds inside.
2019 Update: We’re not starting any warm weather milkweed species by seed this year, but will be starting some perennial milkweed with cold moist stratification
Part 2: Discover a little trick I use to speed up seed germination. (Last year this hot trick got my first balloon milkweed seedlings to sprout after just 3 days!)