Cultivating A Milkweed Garden: Key Techniques & Benefits

Milkweed is crucial for conserving the monarch butterfly, as it attracts butterflies and other pollinators with its fragrant flowers. Each year, numerous monarch butterflies migrate from Mexico to Canada and then return during the autumn season.

Butterflies rely on various types of flowers for nectar, but they exclusively breed on milkweed plants. Of the 140 milkweed species, only a few are considered significant host plants for monarchs, and even fewer are readily available.

About Milkweed (Asclepias syriaca)

Milkweed plants, named for the sticky white sap they release when damaged, are native to the U.S. and Canada, with over 100 species. They play a vital role in supporting various insects, including the Monarch butterflies. These herbaceous perennials produce high-quality nectar and rely on bees, wasps, butterflies, moths, flies, beetles, and true bugs to transfer pollen for seed production.

While Monarch butterflies are among the visitors that seek nectar from milkweed plants, swallowtail butterflies and Nymphalis species are also frequent visitors.

Why Grow Milkweed Plants?

Monarchs are crucial in maintaining a well-functioning ecosystem by serving as pollinators and essential nourishment for birds, smaller animals, and other insects. However, these magnificent creatures encounter numerous obstacles, such as pesticides, the reduction of their habitats, and the effects of climate change.

Planting milkweed is an incredibly effective way to provide support because it is the sole plant that can sustain a monarch butterfly throughout every phase of its life. The nectar in milkweed flowers is a precious source of nourishment for not only butterflies but also bees and other pollinators. It is important to note that butterflies require more than just nectar, especially during their caterpillar stage. The leaves of milkweed plants serve as the exclusive food for monarch caterpillars. Additionally, monarch butterflies rely on the milkweed plant to lay their eggs.

Moreover, milkweed produces a chemical that renders monarchs toxic and unappetizing to certain predators.

Milkweed Plants

How To Plant Milkweed Plants

Plant milkweed seeds in the fall for optimal germination as the combination of cold temperatures and winter moisture encourages growth. Alternatively, milkweed can also be planted in the spring, but in order to simulate the effects of winter, the seeds should first be placed in soil or moist paper towels and refrigerated. This technique is known as artificial stratification.

Seed pods naturally burst open in the autumn, leading to the scattering of the milkweed seeds. The flowers produce seed pods that are typically two to four inches long and have a textured surface, which splits open when they are ripe, allowing numerous small seeds to be dispersed by the wind. To increase the likelihood of milkweed seed germination, it is advised to plant them in a well-prepared soil bed that is free from clumps and has a smooth consistency, achieved by using a rake or rototiller.

Maintain proper moisture in the planting bed until the seedlings are fully established. The seeds should begin to sprout within 7-10 days. Once they have sprouted, thin out the seedlings to 2 inches apart. When the seedlings reach a height of 3-6 inches, they can be transplanted.

Dig a hole that is twice as deep and twice as wide as the root ball. If you are planting multiple plants, you have the option to amend the soil for each individual planting hole or amend the entire bed before planting.

To optimize planting efficiency, arrange plant milkweed in blocks instead of extended rows. Plant milkweed 18-24 inches apart and ensure they are watered immediately after planting, maintaining soil moisture until they take root. Apply mulch around the plants to retain soil moisture and prevent weed growth.

How To Start Milkweed From Seeds Indoors

The cold stratification process, essential for increasing the germination rate, requires 30 days. Hence, it is recommended to start seed stratification in March. Here’s a step-by-step guide on how to do it:

Take the seeds and wrap them in a damp paper towel. Put them in a zippered plastic bag and place them in the refrigerator for 30 days without disturbing it.

Fill peat pots about 3/4 of the way with seed-starting potting soil. Make sure the soil is damp but not overly wet. Put one or two seeds in each pot and cover them with 1/4 inch of soil. Water the pots from the bottom by adding 1/2 inch of water to a flat pan and placing the pots on top. This allows the pots to absorb the water. Choose a sunny windowsill, grow lights, or a greenhouse to place the pots. Keep the seeds consistently moist and expect to see sprouts within two weeks.

When spring comes, transplant the peat pots directly into the ground. The pots will naturally break down over time without causing any harm to the milkweed roots.

How To Care For Milkweed Plants

Milkweed plants are hardy and require minimal maintenance. Typically found in grassland prairies, where resources are limited and plants must compete, milkweeds have developed a strong ability to survive in nutrient-poor soil, dry conditions, and intense sunlight.

The aggressive spreading and tendency to become weedy make common milkweed a less suitable option for formal perennial borders. However, it thrives in naturalized areas such as open fields, meadows, and butterfly gardens.


Milkweed thrives under full sunlight, making it most suitable for open spaces that receive six to eight hours of sunlight daily.

Soil & Water

This particular plant thrives in dry to medium average and well-drained soil. It can tolerate both dry conditions and rocky or infertile soil. It thrives best in soil with a pH range of 4.8 to 7.2.

Additionally, it is crucial to note that milkweeds take a long time to emerge in the spring. It is, therefore, vital to be mindful of their location to avoid causing harm to the delicate new growth.


Milkweeds typically do not require fertilizer. By applying a layer of compost during spring, all necessary nutrients can be provided while simultaneously preventing weed growth.

Pruning Milkweed

Seedpods start to form upright after the milkweed flowers have faded. To prevent milkweed from dominating your garden, removing the milkweed pods in the autumn before they burst open and disperse their seeds or binding them securely with a piece of string is advisable.

It’s easy to pluck or trim the milkweed pods in the first stages as they develop. When the outer florets of the umbel, which is the cluster of flowers, start to form pods, cut the entire stem right back to the first group of leaves beneath the flower stem. This is the most effective method to encourage another round of blooming.

For those plants with rhizomes, manually thin them out by uprooting the whole plant, including the roots, and strive to eliminate as much of the rhizome as possible. This task can be accomplished more comfortably when the plants are still young and their roots haven’t been firmly established.

A close up of a milkweed flower

Milkweed Pests & Plant Diseases

Milkweed bugs, which are usually red or black, and beetles like the swamp milkweed beetle, prove problematic for milkweed and can be found feeding on their leaves, stems, and seeds. Though these insects can cause some damage, they’re not typically a serious threat to the plants. However, Oleander or milkweed aphids can pose a threat, especially to milkweed seedlings.

When Monarch caterpillars arrive, they lay their eggs and feast on milkweed plants, which can leave the plants looking a bit untidy. Regardless of this, it’s crucial to remember not to use pesticides on milkweed plants, or any other plants in a pollinator or butterfly garden, because the same substance that kills harmful insects can also destroy butterflies and their larvae. Neonics, or neonicotinoids, are particularly harmful as they infuse themselves into all parts of a plant. Consequently, when monarchs ingest the poisoned nectar, the results can be harmful and often fatal.

A preferable alternative to pesticides is to remove pests by hand. If aphids are causing significant damage, you can cut off the infested stems or use a garden hose to blast them off.

Moreover, be on the look out for fungus-related issues like leaf spot, verticillium wilt, and root rot. Remove leaves and branches displaying signs of leaf spot, but managing the other two fungus concerns can be challenging.

Some Milkweed Species

  • Swamp Milkweed – It is a long-blooming perennial with delightful mauve, pink, or white blooms. Plant swamp milkweed in a rain garden as it thrives in well-drained soil when watered frequently and in swamp-like conditions. It can grow somewhere around 1-2 meters tall.
  • Showy Milkweed – The Showy Milkweed stands at a height of 0.3 to 1 meter and features blooms in shades of rose-purple and pink.
  • Butterfly Weed – It has blazing orange blooms that blend perfectly with red, yellow, and other vibrant colours in the perennial border. Its height reaches up to 1 meter.
  • Common Milkweed – Common milkweed is the most recognized species. However, it should only be planted if ample space is available, as this plant propagates through seeds and its travelling roots, which may be invasive in a garden environment. It grows to be between 0.6 and 1.5 meters in height and 24 to 36 inches in width.
  • Tropical Milkweed – This non-native milkweed, boasting a vibrant display of red, orange, and gold flowers, is a contentious topic. The reason for the controversy is that its perennial growth in the warmest regions disrupts the standard migration routines of monarch butterflies.
  • Mexican Whorled Milkweed – The Mexican whorled milkweed, which is indigenous to the northwestern U.S, stretches south to Baja California and north to Arizona. It reaches a height between 0.3 to 1 meter and presents blooms in light pink, purple, and white hues.
  • Poke Milkweed – This milkweed, found in damp woodland environments, shorelines, and the edges of forests, typically flowers from late spring into early summer, revealing green and white blossoms.

FAQs About Growing milkweed

How Many Milkweed Plants Do I Need To Grow To Support The Monarchs?

No definitive answer. It is typically assumed that a single milkweed plant sustains one monarch caterpillar. However, the diversity in size, leaf form, and growth speed among the species, coupled with the monarchs’ propensity to lay several eggs on one plant, suggests that planting multiple milkweeds would be beneficial to ensure consistent plant availability throughout the season.

How To Recognize Monarch Caterpillars And Eggs

Monarch caterpillars can be recognized by their distinctive yellow, black, and white stripes. They lay their tiny white eggs either on the tops or bottoms of leaves. Moreover, by planting milkweed in your garden, you may attract not just monarchs but also milkweed tussock moths or caterpillars.

Where’s The Best Place To Grow Milkweed Plant?

The suggested best practices for growing milkweeds recommend planting them in the areas of your yard or garden that receive the most sunlight. With soil quality, many milkweed species flourish in light, well-drained soils if you have an option.

Start Growing Your Milkweed Garden

The placement of milkweed plants in your garden has a significant impact on the visibility of monarch butterflies. By grouping six or more milkweed plants together, you are effectively increasing their chances of attracting these insects.

It’s crucial, though, to prioritize your safety when handling milkweed plants. Don the appropriate protective gear such as gloves, long-sleeved shirts, and long pants. It’s equally important to maintain personal hygiene by making sure to thoroughly clean your hands after each interaction with these plants.

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