Can I Grow My Own Milkweed?
Seed from the Common Milkweed plant. Requires cold stratification, lots of light and some luck to germinate.
The simple answer is of course...however, it requires patience, timing and just the right conditions.
Milkweed is a perennial plant that grows from a small seed.
Seeds are released from milkweed pods at the end of the growing season. Each seed is attached to a silky tendril to help it catch the wind as part of nature's seed dispersal method to spread seeds. Seeds spend the remaining Fall, Winter, Spring on the ground's surface. Milkweed seeds germinate in nature when the soil reaches and maintains a temperature of 65-70° F. This is often late in the Spring in the mid-Atlantic US.
Growing Your Own Milkweed
The easiest part of growing milkweed is buying the seeds; the rest is far more difficult. Your success in germinating seeds that grow to adult plants in the first year depends on how well you mimic the seed's natural environment for 7 months before it even sprouts!
Seed Storage
Growers overwinter their seeds in the refrigerator to simulate Winter conditions. Seeds will likely not germinate if you don't chill your seeds before planting them. In addition to keeping them in the refrigerator, seeds require a cold and damp period of at least 4 weeks. One technique is to dampen a paper towel and place your seeds apart from each other on the paper towel. Next, slide the paper towel into a bag with a closing mechanism. You want to balance keeping the seeds damp but not wet and keep the paper towel from drying out. Mold and mildew will end your chances with this sample of seeds. Moist sand can also be used effectively.
Timing
Timing is critical. If you begin germinating your seeds too early, there will not be enough direct sunlight from any of your windows to keep your new seedlings from reaching for light and becoming 'leggy'. Milkweed sprouts grow quickly in the first 24 hours. If your seedlings stem grow too long the after their first two leaves, the plant will likely not survive. Watch for "damping off" at this stage which is caused by bacteria or fungi in the soil. This disease will kill your plant. Keep seedlings well ventilated and not too wet.
Asclepias tuberosa
Common Milkweed (Asclepias syriaca)
Once you see this, you need to get the seedling under a strong grow light. If you're impatient, like me, you'll scramble for the brightest light possible to keep the plant stocky and develop its first two true leaves. Since most of us don't have a greenhouse or special grow lights, your best option to start seeds is to do so when you can place the plants in direct natural sunlight. I've found it is helpful to place a heating pad under your plant trays to warm the moist (but not wet) soil to 75° F. Be careful not to have the new roots too close to any heating unit which is difficult as heating units heat from below and the surface soil will be cooler.
Note the size of the plant to the left of this text. More importantly, note the tap root extending below the pot level. The tap root is extremely important to a growing seedling. Increasing the pot size of your seedling needs to be done to meet the fast-growing tap root. Use the image to the left as a general guide when to upgrade to a larger, deeper pot.
Be Patient - Milkweeds are late sleepers
Milkweeds emerge from cold spring soils around Mother's Day. By this time, most all other garden weeds have had a few weeks to a month head start. This is important for several reasons. It's not uncommon for gardeners to weed out all spring weeds and not see emerging milkweed plant shoots and accidentally crush them. A second concern is gardeners assume their milkweed failed to make it through the winter and plant something in their place.
The plant to the left shows a rather advanced set of shoots taken May 13th. One should use the calendar only as a backup for predicting when milkweed will emerge. Temperature is the trigger for milkweed to wake up and begin to grow. Consistent 65F or higher soil temperatures are what milkweed need to emerge. Something gardeners need to remember that many early spring weeds do not live long after they've gone to seed. While difficult, a few weeds early in the season may be worth leaving and letting your milkweed catch up to them.
Transplanting
Rule number one - milkweed plants do not like to be disturbed. This include milkweed plants of all stages. Most milkweed have a long tap root. Knowing this, you'll want to transplant your seedling carefully before the seedling tray or pots you're using become too root bound. Seedlings should be planted with the knowledge of how wide the plants will be when they're adult plants. Remember, milkweed don't like to be moved so once you've planted your seedling, you should live with it there.
A final word on growing your own milkweed. Germination rates vary by species. 2022 seed germination results below show wide variability of germination rates with: proper winter storage and spring greenhouse growing conditions.
Seeds Planted % germination rate*
Common Milkweed 97%
Orange Milkweed (butterfly weed) 62%
Swamp White Milkweed 27%
Swamp Pink Milkweed 13%
* results vary significantly year to year as one seed stock may be better than another.
Seedlings require consistent moisture their first year (even drought resistant species such as Asclepius tuberosa) until their root system becomes established. Milkweed do not need plant food or fertilizers. Milkweed seedlings are typically left alone by birds and insects with the exception of aphids. Aphids should be moved by hand on seedlings and very young milkweeds as they will stress the plant
July 2, 2022...
Once you've caught the monarch butterfly & milkweed bug, you'll find yourself looking for and finding milkweed during walks, drives to the grocery store or bike rides. Just the other day my daughter called me and said, I'm seeing more and more milkweed now I know what to look for. That's when I knew I did my job as a father.
Even to the well trained, Nature can trick you and me...but not Monarchs. The plant to the right often grows alongside common milkweed and looks just like the type of plant a female monarch would lay her eggs, but she never does. The plant even has a white latex type of internal fluid. It is not a milkweed plant.
Don't be tempted to dig this out of a nearby hillside, it will not meet the needs of female monarchs nor their young. This said, if you're looking for a leaf of milkweed to feed a monarch caterpillar you're raising - pass on this plant.
Hemp Dogbane...
is not a true milkweed and will not meet the need of monarch butterflies