A type of herb that forms beautiful meadows – milkweed is the go-to plant for boosting the appeal of any garden.
It is an easy-to-grow, quick-spreading, and sturdy plant in every way. But despite being such a practical species, milkweed can be a bit problematic.
If you don’t know how to grow milkweed, it could be overwhelming and frustrating. This happens because milkweed has a few specific requirements that other plants don’t. If you don’t know them, growing it becomes a problem.
To prevent that, we’ve assembled a guide with everything you need to know about milkweed. Want to know what we’ve gathered? Then keep reading!
What is Milkweed Exactly?
There are many names for milkweed, such as silkweed, butterfly flower, silky swallow-worth, and many others. Either way, it comes from the same species, “Asclepias spp.”
Its name “milkweed” comes from the zap the flowers produce when disturbed. This zap is the nectar that attracts all kinds of animals.
This plant stands out for three reasons. One is the uniquely attractive appearance despite being an herb. When its flowers grow, the plant can make any place a lot more appealing.
The second reason is the capacity to grow anywhere. Despite being a sub-tropical plant, it can withstand different environments and temperatures without problems. What’s even more interesting, it spreads super-quick – just like weed.
Third, it is the favorite plant for the Monarch butterfly to lay its eggs. If planted in a meadow where these butterflies pass through, you’ll likely create a butterfly garden without any effort.
Apart from all that, milkweed is an American species, mainly found in the US and Canada. It has over 100 different species that vary in growth and color. And more importantly, it withstands pests, diseases, and even harsh climates where other plants would falter.
Types of Milkweed to Consider
We mentioned that milkweed has 100 varieties. And that’s true. But we can’t go over all of them. For that reason, you’ll find the most popular below, with info about their growth, appearance, and needs. Check them out:
Butterfly Milkweed (Asclepias tuberosa)
As the name says, this variety is one of the most attractive to insects, especially butterflies. It produces gorgeous flowers that can achieve an intense red-to-orange color that’s impossible to dismiss.
The plant grows like a bush with individual stems that can grow to 3 feet in some cases. Interestingly, it can grow to these heights in any soil. But it still prefers dry conditions, especially from the Southeastern of North America (where it is from).
California Milkweed (Asclepias californica)
Probably the rarest of all milkweed species, the California milkweed is one of the few varieties that’s native from the Western area of North America. You can find it pretty much all across California.
The exciting part about this species is the dark-purple to pink flowers. These flowers are not only excitingly colorful, but they’re also webby.
It has the thickest leaves and stems, grows to 3 feet in height, and loves arid areas with high altitude to make it even more strange.
Common Milkweed (Asclepias syriaca)
Probably the tallest milkweed, the most popular, and the easiest to grow. This variety can reach 5 feet in height, grow in almost any type of garden soil, and appreciate relatively humid or dry environments.
The flowers are often white or yellow, with rare cases growing in purple. These flowers grow on entirely green leaves with fleshy stems.
It is also one of the favorite plants for insects, especially butterflies. Because of that, you can find it in the East, Midwest, and South of North America.
Purple Milkweed (Asclepias purpurascens)
When the plant is fully mature and blooms, the flowers achieve a pink-to-purple color. Thus, it gets such a particular name.
This species has a unique advantage: it thrives under shade. Most milkweeds require consistent sun exposure, while this one can grow in sub-tropical environments with little sunlight.
Its leaves are green and veiny, just like the stems. Yet, it is one of the smallest, typically growing 3 feet at its max.
Showy Milkweed (Asclepias speciosa)
One super-rare but lovely type of milkweed is the showy species. It is native to Western North America and prefers arid places with relatively warm climates. However, it can also grow in more humid areas with colder temps.
The plant can reach 6 feet in height. More interestingly, it produces some of the cutest flowers that boast a furry appearance. These are often pink but can have shades of white and purple. The leaves are usually pale green and veiny.
Swamp Milkweed (Asclepias incarnata)
The second most popular variety of milkweed, the swamp type boasts intense pink to dark-purple flowers. It can grow to 5 feet, and it prefers humid environments (like swamps or close to ponds).
The exciting part about this plant is the leaf shape. In contrast with others, this one has thin stems and narrow leaves compared to others. These leaves are often lance-shaped, making them uniquely attractive.
Apart from that, it grows in individual stems instead of bushy like other varieties. It is also highly appealing to insects.
Tropical Milkweed (Asclepias curassavica)
Known by many names, such as cotton bush, blood flower, Mexican butterfly weed, and scarlet milkweed, this is another hugely popular variety to consider. This happens both for its beauty (thin leaves, orange-to-red gorgeous flowers) and its capacity to grow anywhere.
While it prefers humid environments, it can also handle dry places. Either way, it thrives in full sun and high temperatures. The plant doesn’t grow more than 3 feet or so.
It prefers Southern and Western North America. And it is one of the Monarch’s butterfly’s favorite too.
Is Milkweed Toxic?
If you’re asking whether milkweed is edible – the obvious answer is no. Despite being a perennial herb, it contains a wide array of toxins on its leaves, stems, and flowers that aren’t necessarily safe to consume.
The plant is considered poisonous not only to humans but also to a wide array of other animals, including deer and other large mammals.
Consuming milkweed can cause breathing problems, dilated pupils, muscle spasms, bloating, fever, and sometimes life-threatening symptoms. For that reason, it is wise to use it only as an ornamental. At the same time, it’s worth keeping away from pets and children.
What Does Milkweed Need to Grow?
You may already have a general idea of what milkweed requires to thrive. But because we want to make it as straightforward as possible, here’s a comprehensive guide to follow:
Spacing & Container
One of the most important aspects to consider is the are where you’re growing it. Milkweed requires a lot of space as a weed-like perennial. When planted in small areas, it tends to overcrowd fast and eventually root away from the place.
That’s why it’s worth planting in gardens instead. If you plant in a container, it may be difficult to transplant later on. Because it produces deep tap-roots, the plant doesn’t like transplantation.
Generally, it’s worth planting in spaces of at least 18 inches in diameter. If you’re planting several milkweed plants at once, put them at about 36 inches apart.
Soil & Fertilizer
Most milkweed varieties will grow in practically any soil. As long as the soil has sufficient nutrients, the plant will thrive. If you can make your own potting or garden soil, that would be a huge plus.
Some varieties like the swamp milkweed will prefer damp soil. But even then, it can also grow in arid places with the right environment.
As for fertilizer, you will need none. You can use it as a plus, but it’s not required nor recommended. The plant grows in poor soils without problems.
Watering & Humidity
You won’t have to be continually watering milkweed. As long as you irrigate the once a week, it should thrive seamlessly well.
But this also depends on the variety. Some species will require a lot more moisture to grow. For them, we recommend watering once daily.
Generally, though, milkweed likes arid areas. If you go for common or butterfly milkweed, you won’t need much humidity.
Light & Air
As a perennial herb, milkweed requires a lot of sunlight. This means at least 8 hours of sun exposure to thrive.
Having said that, the humidity-loving species and the smallest ones can grow in partial shade (4 hours or less of sunlight).
One particular thing about milkweed is the dislike of wind. Especially when blooming, milkweed doesn’t appreciate windy areas as it keeps away pollinating insects that it depends on.
Temperature & Environment
Milkweed is generally a hardy perennial. This means it will grow practically anywhere with temperatures ranging from 30-degrees to 85-degrees Fahrenheit. However, it also depends on the species you pick.
The swamp variety prefers moderate warmth of about 40 to 70 degrees. A common milkweed plant won’t resist temperatures lower than 30 degrees. And the tropical species require temperatures above 60 degrees to thrive.
Because of its rapid growth, reliance on sunlight, and capacity to attract animals and insects, milkweed is mostly an outdoor plant. Growing it indoors (like a terrarium or greenhouse) can be problematic to the point of impossible.
How to Grow Milkweed in 5 Steps
Now that you’re aware of everything milkweed needs, you’ll have a blast planting it and watching it grow. This is what you need to do:
1. Choose Growing Method
First off, decide whether you want to plant the milkweed from seedlings or seeds. The process will vary depending on what you pick.
For example, growing from seedlings is often done in the spring. Here, the plant will probably be dormant (no green leaves – only a stem). This one will be about planting and letting the stem establish on the soil with its roots. It can take anywhere from 1 month to 2 months to see flowers.
If you’re growing from seeds, you will have to start in the fall. This helps the plant germinate better as it will stratify the seeds (soften them up) so they’re ready for sprouting by spring. This process may take a bit more than using seedlings, generally growing after the second month.
2. Prepare the Soil
With the desired planting method in mind, it’s time to prepare the soil you’re going to use.
Because milkweed doesn’t require anything special, you will probably need to do nothing. As long as the soil seems nutritious and sandy, that should be enough.
Having said that, we recommend loosening the soil a bit. At the same time, clean the area from weeds as well as rocks and mulch. The focus is to ensure proper humidity and a sufficiently compact but still loose soil for the plant to thrive.
3. Plant the Seed or Seedling
The soil is ready for planting, then you should start opening the hole. Whether you begin by seed or seedling, you’ll have to open a large-enough hole of about 1 inch in diameter.
Wet the soil a bit and compact the borders. Then you can place the plant or seed inside the hole. If you’re using seeds, cover the hole with some mulch for extra moisture in the fall and winter. This should quicken the stratification.
For seedlings, just cover the bottom of the plant and compact the soil a bit. The root ball should be just above the soil level.
4. Water Right Away
As soon as you plant the seed or seedling, you’ll have to pour some water on the area. Even though the plant thrives in arid environments (most species), it will need a lot of moisture at first. This is especially true if you’re starting from seeds in the fall.
You should keep watering the plant every 2 or 3 days. This will keep it nourishing from the soil more effectively.
5. Let it Grow
You’re practically done with the milkweed. It shouldn’t take more than a month to start growing over 1 or 2 feet (depending on the variety).
Either way, you should leave it alone. Apart from watering almost daily, you should leave it to grow without disturbances. This is helpful for both seeds going through the winter and seedlings growing in the spring or summer.
Otherwise, it may last longer to establish and grow roots. When it struggles, its growth stunts – which you don’t want.
How to Care for Milkweed
This plant requires little to no care. However, you can make it grow quicker and much more attractive with the right guidance. Here are a few tips to consider:
There’s one rule of growing milkweed everyone should follow: it hates transplantation. Due to the deep tap-roots it produces once it establishes, transplanting it can be fatal. We don’t recommend doing it once it fully matures.
Milkweed depends on pollinators like butterflies to spread, so it will be consistently attracting insects. This means a lot of eaten leaves and flowers. If you don’t want that to happen, spray water over the pests and that should get the job done.
Keep it from Overspreading
When it overspreads, the younger plants eventually struggle to grow well. It’s better to keep a couple of milkweed plants that grow beautifully than an entire garden of low-hanging ones. For that, prune it consistently and get rid of unwanted sprouts around.
Add Some Mulch
One enemy of the milkweed is the growth of weeds around. You can control them with some mulch (you can always use a homemade weed killer). If you’re planting humidity-loving varieties, mulch can also help to keep the soil moist.
Clip Used Flowers
If flowers die out and lose their color, you can always clip them off. This will encourage new blooming and keep the plant flourishing more beautifully.
While it requires half the care of other plants, milkweed still requires some love. If you want to grow it at home, then you better follow our advice above.
We hope you learned how to grow milkweed and everything else related to this plant’s beauty and interesting facts.
Because your garden needs it, you shouldn’t waste any time. Start growing today, and you’ll be stoked when butterflies and birds start feeding on the milkweed next spring.