You shouldn’t judge a plant by its name. That’s certainly the case with this wildflower that’s not actually a weed. This tough native of North American fields, wetlands, and prairies is the only host plant for the struggling monarch butterfly.
According to Aunrag Agrawal, author of Monarchs and Milkweed, summer in a milkweed patch is a beautiful and fragrant place, where bees are constantly buzzing and monarch butterflies often rest on the flowers. Agrawal also says that it’s not uncommon to find monarch caterpillars grazing on milkweed leaves.
MILKWEED BASICS
Milkweeds get their name from the sticky white sap that oozes from the leaves when they are damaged. More than 100 species of this herbaceous perennial are native to the U.S. and Canada.
Types of milkweed:
Three species of milkweed are good all-around choices for gardens in most regions of the country:
- Common milkweed (A. syriaca)
- Swamp milkweed (A. incarnata)
- Butterfly weed (A. tuberosa)
There are many different types of milkweed that are both decorative and easy to take care of. You can find out which ones are best for your area by downloading this information sheet from the Monarch Joint Venture website.
You should avoid tropical milkweed (Asclepias curassavica) as it can harm monarchs. You can read more about it from the Xeres Society.
Flower characteristics:
The small, star shaped flowers on milkweed are designed for pollination. depending on the plant, the flowers can be yellow, green, purple, pink, or orange. The large seed pods that develop from the fertilized flowers are also well designed. In the fall, these pods open and release hundreds of seeds.
Height:
2 to 5 feet, depending on the species
Zones:
3-9
Attracts:
Besides monarchs, frequent visitors also include native bees, honey bees, hummingbirds, and many other types of butterflies. Read more about
the best perennials for pollinators.
Why it’s a must for monarchs:
The milkweed plant provides food for monarch caterpillars and also hosts the eggs that are laid on the underside of its leaves. After hatching, the caterpillars feed on the leaves; however, they do not cause any permanent damage to the plant. The toxic chemicals in the milkweed sap make the caterpillars and adult butterflies unappetizing to predators.
The monarch’s flight during migration is powered by their nectar intake from flowers, with periodic egg-laying on milkweed plants. Agrawal states that milkweed is the only sustenance the monarchs need for growth and survival.
MILKWEED CARE
Growing milkweed is easy and it does not require much care. It is not damaged by heat, drought, deer, or other pests. Also, milkweed can grow in poor quality soil, so adding fertilizer is not necessary.
Mulching:
If you mulch milkweed, it will help control weeds and retain moisture. However, not all varieties of milkweed will benefit from mulching. Those that prefer dry soil, such as common milkweed and butterfly weed, are usually better off without mulch.
Pruning:
To encourage more blooming, remove withered flowers from the plant. This will also provide more nectar for Monarch butterflies and other pollinators. Cut the flower cluster off just above the first set of leaves.
Pest control:
Some plant pests, such as aphids, whiteflies, and milkweed bugs, are immune to the toxic effects of milkweed and may feed on the leaves and seed pods, but they rarely cause significant damage. You can also remove leaf litter and spent stalks in the fall to eliminate overwintering sites.
How to control spreading:
To prevent milkweed from taking over your garden, remove the seed pods in the fall before they open and release their contents, or tie them closed with string. For plants with rhizomes, thin them out by pulling the entire plant, including the roots, and removing as much of the rhizome as possible. This will be easier to do when the plants are young and before the roots are well established.
Handling precautions and toxicity:
The toxic chemicals in milkweed that help protect monarchs can also cause skin and eye irritation. They can also be poisonous to pets if ingested, so take precautions when working with milkweed plants.
Choosing the right milkweed for your garden
To help the monarchs, plant native milkweed in your garden.
Many people make the common mistake of planting non-native milkweed.
One of the most popular milkweed species, Asclepias curassavica or tropical milkweed, is widely sold in nurseries, but it’s been found to do more harm than good.
When grown in warm climates, the year-round tropical milkweed encourages monarch butterflies to stay in the Southern United States rather than migrate to Mexico.
Caterpillars that hatch and feed on tropical milkweed are more likely to be infected with a protozoan parasite called Ophryocystis elektroscirrha (OE), which makes them weaker as adults.
OE is found in all species of milkweed, but Caterpillars only eat the leaves in the early stages of growth. Once the plant goes dormant in winter and loses its leaves, OE is no longer a threat.
Although the leaves of tropical milkweed stay alive during winter, this increases the likelihood that caterpillars will become infected.
COMMON NATIVE MILKWEED SPECIES
Common milkweed is a plant that grows 3 to 6 feet tall. It is native to the eastern United States, but can also be found in other parts of the country, such as Georgia, Tennessee, Kansas, and Iowa. The plant has white and purple blooms.
Additionally known by the scientific name Asclepias tuberosa, butterflyweed is a native plant that can be found in areas of the northeast and eastern United States, as well as south to Florida, west to Texas, and north through Colorado to Minnesota. This plant grows to be 1 to 2 feet tall and has light orange blooms.
The flowers are followed by seed pods that explode when they mature, scattering their seeds up to 20 feet. The swamp milkweed (Asclepias incarnate) is a native plant from the northeast United States south to Georgia, west to Texas, and north to North Dakota. It grows 4 to 5 feet tall and has mauve, pink, or white blooms. The flowers are followed by seed pods that explode when they mature, scattering their seeds up to 20 feet.
Asclepias humistrata, or sandhill milkweed, is a native plant from the southeast United States that can grow up to 1-3 feet tall. It has pink, lavender, or white blooms.
Asclepias speciosa, also known as showy milkweed, is a plant native to the western United States. It grows 1 to 3 feet tall and has rosy-purple and pink blooms.
The Mexican whorled milkweed is a native plant to the northwestern United States. It grows to a height of 2 to 3 feet and has pale pink, purple, and white blooms.
You will often find Butterflyweed growing in dry and sandy soil with little nutrition. It does well in these conditions because it is drought-tolerant. This makes it a good choice for low-maintenance perennial gardens.
I have had experience growing a few types of milkweed over the years, most notably butterflyweed, and have been struck by how tough they are – not only can they withstand extreme heat, but also attacks from oleander aphids and milkweed bugs, as well as being regularly eaten by striped caterpillars. It doesn’t take many caterpillars to strip a milkweed plant of all its leaves in a couple of weeks, but somehow it always manages to regrow.
If you want to plant butterflyweed but it’s not native to your area, or you want to add more variety to the milkweeds in your garden, visit a native plant nursery or look for seeds from a local vendor. You can also find seeds online from the Xerces Society’s Milkweed Seed Finder or Botanical Interests.
GROWING MILKWEED
Where to plant:
-Locate milkweed plants in an area of the garden where they can be better controlled to prevent them from spreading too much. -It’s best to put them in a spot that gets a lot of sun and is protected from the wind. -Keep in mind that milkweed plants have a taproot and don’t transplant well.
When to plant:
If you want to plant milkweed from seed, it’s best to sow them outdoors in the fall. By doing this, the seeds will be exposed to the cold, moist conditions they need to germinate in the spring. This will also help ensure that the plants will produce a good display of flowers the following summer. If you purchase starter plants, plant them in the spring after the danger of frost has passed.
How to plant:
To plant milkweed seeds successfully, make sure the soil is 2016 smooth and without clumps. Use a rake or rototiller to make it fine and consistent. Once you have sown the seeds,Compact them slightly into the soil so there is good contact between the seed and the soil. Keep the planting bed moist until the seedlings have time to begin growing strong. After they have started to grow, thin out any plants that are too close together so they will have enough sun and nutrients.
Propagating:
Many milkweed species can be propagated via root or rhizome cuttings, as well as by seed. Cuttings should be taken during the late fall or early spring when the plant is dormant and has more energy reserves. New sprouts will form from the cuttings when the weather warms and will often produce flowers the first year.
Light
The ideal location for milkweed plants is one that gets six to eight hours of sunlight per day.
Soil
Each milkweed variety prefers a different type of soil.
- Butterflyweed and Mexican whorled milkweed grow best in dry conditions.
- Swamp milkweed thrives in a moist environment, as its name implies.
- Sandhill milkweed prefers dry, sandy soils.
- Showy milkweed and common milkweed grow well in average garden soil.
- Tropical milkweed prefers hot, humid conditions, but can be grown as annual in cooler climates.
Spacing
Though milkweed plants have large, deep root systems, they don’t do well when transplanted. Most species should be planted 18 inches apart.
Swamp milkweed, if left to mature, willgrow in clumps up to 36 inches wide and should be spaced 30 to 36 inches apart. You can also plant swamp milkweed and its cultivars closer together and thin the plants as they grow.
Watering
Other than swamp milkweed, most milkweed species don’t need much water and can even tolerate dry conditions.
It’s a good idea to wait until the top inch or two of soil is dry before watering again. Water deeply and make sure the water drains well.
Fertilizing
This plant is easy to take care of and can grow in most soils. You don’t need to worry about it too much, just sit back and enjoy it!
How to grow milkweed from seed
Unlike other flower seeds, milkweed seeds cannot simply be thrown out in spring and expected to grow; one must be patient, as it will take some time.
One of the most common mistakes people make is not cold-stratifying their milkweed seeds.
To start milkweed from seed, it is easiest to sow the seeds in place in fall after the first killing frost (typically in November). This allows the seeds to go through a period of cold stratification over winter and then germinate in spring.
| The Old Farmer’s Almanac In order to find out when the first and last frost dates are, you can use this custom planting calendar.
You can start milkweed seeds in the spring by cold-stratifying them in the refrigerator if you live in a warm zone without frost.
To plant milkweed seeds, place them in a damp paper towel or paper coffee filter, seal them in a zip-top bag, and refrigerate for 30 days.
You can sow the seeds either directly outside or start them indoors and transplant them later. Milkweed seeds can take up to two weeks to germinate, so be patient!
