The Ultimate Guide to Butterfly Milkweed Plants
Butterfly Milkweed, known as Butterflyweed, Pleurisy Root or Asclepias tuberosa, is a perennial flowering plant that is native to nearly all of the United States and will grow up to 2 feet tall in USDA planting zones 3-10. Butterfly Milkweed has suffered severe habitat loss in the US and has been driven to extinction in southern New Hampshire, southern Vermont and southern Maine. Butterfly Milkweed gets its common name due to its popularity as a nectar source for Monarch Butterflies and also serves as a host plant for Monarch Butterfly caterpillars who enjoy feeding on their foliage.
How to Grow Butterfly Milkweed
Butterfly Milkweed can be tricky to both grow from seed and transplant from a nursery (like New Leaves) if you don’t get the timing right.
How to Grow Butterfly Milkweed from Seed
Growing Butterfly Milkweed from seed typically requires cold moist stratification. This means that if you’re growing them yourself, you’ll either have to sow seeds outdoors in the fall immediately after your last hard frost, or you’ll have to mimic the way Mother Nature would interact with each seed to break dormancy.
Artificial cold, moist stratification can be achieved by mixing seeds with some type of sterile growing medium like damp sand and placing that mixture inside of a sealed plastic bag. You’ll then store that mixture inside of a fridge at 33-34 degrees F for around 30 days. You’ll need to check on the seeds periodically to ensure that they haven’t broken dormancy. Once your seed breaks dormancy, you’ll want to plant immediately in soil.
Another method of growing Butterfly Milkweed from seed that works with less certainty is to place the seeds in a glass of distilled water then placing the glass on a germination mat for 3-5 days. You should be able to break dormancy utilizing this method, however, it is not recommended for the highest germination rate.
How to Grow Butterfly Milkweed Plants
As noted before, Butterfly Milkweed can be very finicky and requires specific soil, sun and timing conditions to grow correctly.
When to Plant Butterfly Milkweed
Butterfly Milkweed is best planted in the late spring to early summer if you’re transplanting from a growing pot. You’ll want to make sure that the soil temperature is above 60 degrees for the best results.
Where to Plant Butterfly Milkweed
When transplanting a seedling or plant from a nursery or grower, your planting location is essential to its survival. Butterfly milkweed thrives in full sun, meaning 6+ hours of direct sunlight with a preference of morning sun and protection from hot, mid-afternoon sun. They can grow in conditions with less sun, but I wouldn’t expect to see many of their striking orange and yellow flowers.
You also want to make sure that your location has a soil mixture that is a loamy and slightly sandy type that ensures good drainage. I recommend planting Butterfly Milkweed with a mixture of compost and the surrounding soil to add moisture retention and slow-release nutrients.
Once you find the spot with the right sun and soil conditions, make sure that the hole that you dig is about the same depth as the soil of the potted plant. Make sure the soil level of the potted plant is slightly below the surrounding soil surface. Then fill in the soil mixture around the plant and make sure to pack down the soil to ensure no air bubbles are present.
Butterfly Milkweed Care
Watering your Butterfly Milkweed correctly is also super important. If you are planting a dormant plant (i.e. you received it in the early to mid-Spring) make sure that you are not over-watering. This is where a soil moisture meter comes in handy. However, if you don’t have a moisture meter, check by placing a finger in the soil up to the first knuckle. If you feel moisture, then wait to water.
Finally, MULCH! Using wood or straw mulch is very important when it comes to regulating moisture levels, preventing competing weed growth and protecting roots from heat and cold. You’ll want to have 3-4 inches of mulch surrounding your Butterfly Milkweed for the best results.
Transplanting Butterfly Milkweed
If you’re trying to dig up and transplant a Butterfly Milkweed plant, I wouldn’t recommend it. Butterfly Milkweed plants have a taproot root system, which is incredibly sensitive to any type of disturbance. That goes for nearly all milkweed species, so if you see milkweed in the wild DO NOT dig it up!
Butterfly Milkweed Bloom Time
Butterfly Milkweed will bloom their flowers between June and August, typically, and will occasionally be late to emerge from the soil in the spring and early summer in northern climates, so make sure to have patience! Butterfly Milkweed may bloom through September and October in warmer climates.
How to Harvest Butterfly Milkweed Seeds
Once the Butterfly Milkweed plant root system and foliage are established, you may find that they alien-looking develop seed pods, which is how Butterfly Milkweed spread and grow into colonies. These seed pods grow through the late summer and early fall and eventually pop open with fuzzy parachutes attached to each new seed.
To harvest, wait until the seed pod pops and remove the pod from the stem. Separate the parachutes from the seeds, collect the brown seeds and place in a dry container. Make sure all of the parachutes are gone to limit the risk of decomposition in storage.
To store your seeds for next season, make sure they are in a dry, cool place (like a basement) to prevent seeds from breaking dormancy. You can also scatter these seeds where you want. For maximum germination from the seeds, you’ll want to scatter them immediately after your last hard frost in northern climates.
Aphids on Butterfly Milkweed
Have you seen little orange bugs on your milkweed? Oleander Aphids are a pest found extensively in the US. Sucking the sap from milkweed leaves and leaving behind a sticky substance called Honeydew. Ants typically hang out around these aphids, as they enjoy the sweet taste of that Honeydew.
Unfortunately, since Oleander Aphids are invasive, they can infest a patch of milkweed pretty quickly if not handled early. Through my research, I found that there are three main ways to get rid of them:
1. Neem Oil
2. Introducing natural predators
3. Insecticidal Soap
Butterfly Milkweed is an incredibly important native plant that needs our help for re-establishment in the US. If you’re interested in getting Butterfly Milkweed plants shipped directly to you, check out our latest deals on Butterfly Milkweed plants for sale online!
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