When, where and how to plant milkweed to save the monarch butterfly
We need to stop the monarch's rapid descent toward extinction
When it comes to saving the monarch butterfly, many people know that milkweed is essential. I’m often asked, “When should I plant it, and does it matter what kind of milkweed?” To answer these and other questions about helping these iconic pollinators, I have compiled this compendium of much of what you need to know.
First things first, it’s important to understand what’s at stake with the monarchs. These breathtaking orange and black butterflies travel up to 3,000 miles on its journey across North America. Their populations have seen an alarming drop in recent years. Across the region falling east of the Rocky Mountains, the monarch population has dropped approximately 80 percent since the mid-1990s. In the West, population decline since the 1980s is as high as 99.9 percent.
Monarchs contribute to a healthy ecosystem as pollinators and an important food source to birds, small animals and other insects. Yet these creatures face many challenges from pesticides, habitat loss and climate change. While the U.S. Fish and Wildlife Service agreed that protections are warranted, the monarch butterfly has not been given strong national protections yet. With their very existence in danger and no end to these challenges in sight, it is important that we act now to save the monarch butterfly.
Thankfully, we know of some ways in which everyone can help. Along with planting milkweed, there are other ways you can help the monarch.
- Plant more milkweed
- Grow nectar-rich flowers
- Skip the pesticides
- Avoid raising monarchs
- Make a pledge
1. Plant Lots of Milkweed
Milkweed is vital for the monarch’s life cycle. It’s the only plant monarch caterpillars eat. These caterpillars hatch from eggs laid on the plant before consuming its leaves.
However, not just any kind of milkweed will do. The key is this: You must plant milkweed native to your area.
The reason? Planting non-native types of milkweed risks monarch butterfly health. In many areas, non-native, tropical milkweed survives through the winter, allowing ophryocystis elektroscirrha (OE), a parasite that can be found on monarchs and milkweed, to build up to dangerous levels. On the other hand, with native milkweed, the parasite dies with the plant in the winter, ensuring that new milkweed grows with less risk from the parasite when monarch butterflies return in the spring.
You can locate vendors near you to purchase milkweed. Remember, local vendors do not always equal local seeds — ask about the origin of milkweed seeds and plants before you purchase them. Another option, if you have milkweed in your area, is to harvest the plant yourself. Pro tip: To harvest seeds at the right time, make sure their pods pop open under light pressure. These guides can help you identify milkweed native to your area:
When should you plant milkweed? Ideally, the best time to plant milkweed seeds is in the fall so the cold temperatures and moisture that come with winter stimulate germination. You can also plant milkweed in the springtime. However, milkweed seeds planted in the spring need to first be put in soil or moist paper towels and placed in the fridge to simulate the effects of winter. This process is called artificial stratification.
If you are starting your seeds indoors, you should begin growing the plant 4 to 8 weeks before moving them outside. No matter how long winters last in your region, just make sure to wait until after the last frost before transitioning the plants outdoors. If you are using potted milkweeds, plant them after the last frost so that they do not die before the monarch’s mating season.
You should also know where and how to plant milkweed. Best growing practices suggest milkweeds be planted in the sunniest parts of your yard or garden. If you have a choice of soil, most milkweed species thrive in light, well-drained soils with seeds planted a quarter-inch deep. Make sure you check your seed packets or ask your local nursery for special instructions on the type of milkweed you are planting as there are some exceptions. Since milkweed is a perennial plant, you won’t need to replant it every year. You can harvest the seeds from your new plants and grow them in other parts of your yard or garden if you desire.
One final point: If you live north of Santa Barbara within 5 miles from the California coast, do not plant milkweed. Instead, plant nectar-rich flowers that match these areas’ natural vegetation and the monarch’s migration habits.
2. Grow Nectar-Rich Flowers
Once monarch caterpillars transform into beautiful butterflies, they need the right food that can not only assure they survive but that can also power their long winter migration to Mexico or the California coast. Be sure to include flowers that are native to your region, since these are plants monarchs have relied on and are suited to the local environment.
When plant shopping, ask your local nursery if they treat their plants with pesticides because you want to avoid toxic exposure to the monarchs. Our friends at the Xerces Society and their partners, have put together these guides for nectaring plants by region:
- Great Basin
- Great Lakes
- Inland Northwest
- Maritime Northwest
- Northern Plains
- Rocky Mountains
- Southern Plains
3. Don’t Use Pesticides
Even if they aren’t the intended target, pesticides severely impact pollinators like the monarch butterfly.
Neonicotinoids, also known as neonics, are particularly destructive. When applied, neonics spread throughout all parts of a plant, becoming dangerous for monarchs and more. As a result, monarchs feed on the contaminated nectar, leading to harmful and often lethal outcomes.
While places such as Canada and the European Union have restricted or banned the use of neonics, these toxins still have very minimal restrictions in almost all of the United States. Our work to limit neonics in the U.S. continues, but in the meantime, we need to help prevent the exposure of these dangerous products to pollinators. When purchasing yard and gardening products, avoid those with neonicotinoid ingredients including clothianidin, imidacloprid, thiamethoxam and dinotefuran, and neonic-like ingredients, such as flupyradifurone and sulfoxaflor. You can also incorporate some alternative methods to deter pests from your property.
4. Avoid Rearing Monarchs
Raising butterflies is an enticing activity for families and educators, but breeding monarchs in captivity is hurting the species’ survival. Captive-bred monarchs are less likely to survive, and scientists warn those that do survive long enough to mate will pass down their weaker traits to wild butterflies, hurting the chances of survival for the whole population.
Instead of raising monarch caterpillars in your house, you can watch wild monarch caterpillars grow from eggs to butterflies by monitoring the milkweed plants you have just grown in your yard.
So much thanks to Environment America intern, Chelsea Reimers, for her research and writing contributions to this blog.
Pledge: Milkweed for Monarchs
Frequently asked questions about growing milkweed
What month do you plant milkweed?
The best months to plant milkweed are October and November. Milkweed will remain underground over the winter and the cold temperatures and moisture stimulate germination.
Can you plant milkweed seeds in spring?
You can also plant milkweed in the springtime. However, milkweed seeds planted in the spring need to first be put in soil or moist paper towels and placed in the fridge to simulate the effects of winter.
Should I start milkweed seeds indoors?
You can plant milkweed directly outdoors. If you are starting your seeds indoors, you should begin growing the plant 4 to 8 weeks before moving them outside. No matter how long winters last in your region, just make sure to wait until after the last frost before transitioning the plants outdoors. If you are using potted milkweeds, plant them after the last frost so that they do not die before the monarch’s mating season.
What months do monarchs need milkweed?
Monarchs lay eggs in March through as late as October in various parts of their range in the U.S. Monarchs lay eggs on milkweed plants in the southern U.S. in March through May, in the eastern U.S. in April through June and in more norther parts of their range in May through July and again in the south later in the summer. The larvae, or caterpillar feed on the plants in the following weeks.
Where in my yard or garden is the best place to plant milkweed?
Best growing practices suggest milkweeds be planted in the sunniest parts of your yard or garden. If you have a choice of soil, most milkweed species thrive in light, well-drained soils.
How do I plant milkweed seeds? Can I just scatter milkweed seeds?
In general, milkweed seeds should be planted a quarter-inch deep. If you purchased seed packets look on the label or ask your local nursery for special instructions on the type of milkweed you are planting as there are some exceptions.
Do I need to replant milkweed plants each year?
Since milkweed is a perennial plant, you won’t need to replant it every year. You can harvest the seeds from your new plants and grow them in other parts of your yard or garden if you desire.
Senior Director, Conservation America Campaign, Environment America Research & Policy Center
Started on staff: 1991 B.A., Wartburg College Steve directs Environment America’s efforts to protect our public lands and waters and the species that depend on them. He led our successful campaign to win full and permanent funding for our nation’s best conservation and recreation program, the Land and Water Conservation Fund. He previously oversaw U.S. PIRG’s public health campaigns. Steve lives in Sacramento, California, with his family, where he enjoys biking and exploring Northern California.
Former Save the Bees, Associate, Environment America Research & Policy Center