Early August is here, and the Monarchs are swooping down on us. There are endless things to write about in the garden: Joe Pye weed, prairie dock, summer azures, puddling, annual fleabane (still blooming!) -these are all things I was trying to write about, but the monarchs can not be denied. They really have the run of the garden right now, bossing all the other butterflies around. I just saw a monarch and a hummingbird run off a female swallowtail. Grumpiness takes wing.
I am sure that the number one reason we have so many monarchs visit us around this time each year, is the blooming of the meadow blazing star, Liatris ligulistylis. Often referred to as the “monarch magnet,” this plant is no joke! This year, we had monarchs landing on the very first, barely opening blossom.
Funny that when I planted these meadow blazing stars a few years ago, it was a mistake! I somehow mislabeled them (a mix up with shooting stars, you see), so I merrily thought I was planting a twelve inch tall plant under the peach tree and right at the front of the pond bed. These places would have been odd choices for meadow blazing star, a 5ft tall, sort of lanky plant, but they have turned out to be so great because they’re so easy to see from where we like to sit on the deck.
We watch the monarchs come and go, usually I’d say there’s about 4 or 5 or so, chasing each other, swirling around, flying inches overhead, and nectaring on meadow blazing star. They are daily almost bumping into me while they chase each other and mess around. It feels like I’m witnessing special August magic, and I feel so lucky to have this plant and these butterflies in my backyard. I guess what I’m saying here is… you got to plant this plant!
What’s in that nectar?!
Why are they so crazy/the craziest about meadow blazing star? Well after a lot of searching, I think I can say that no one really knows why, nor have they bothered to look into it! As far as I can find, no one has done a nectar analysis of this species, which to my mind, is rather astonishing, but there you are. Pollination ecologists! Restoration ecologists! Somebody with the proper tools! Maybe do this? It feels like an exciting question to me: the most attractive plant to the iconic and threatened monarch butterfly, whose mysterious nectar draws monarchs in from afar, yet no one knows what the monarch seeks so voraciously… is it simply the sugar, or could it be…. something else?! (see? super exciting!)
The make up of nectar is complex. It consists of water, sugars, amino acids, lipids, among numerous other organic chemicals. Each species of flower contains different ratios of these components, and so each species has unique nutritional benefits, and no doubt a unique flavor. A number of studies have shown that amino acids in nectar are particularly beneficial for butterflies, playing a role in increasing lifespan, egg production, egg size, larval size, and even increasing survival in some butterfly species. And so, what is the secret formula of meadow blazing star nectar? Hopefully, we’ll find out some time soon.
In the meantime, nothing should stop you from planting many, many meadow blazing stars, and changing your life and yard with beautiful, dancing monarchs.
Growing Meadow Blazing Star
Meadow blazing stars are really easy to start from seed with a 2 month cold treatment. They’ll look like a blade of grass the first year, but will very likely bloom the second year (if you don’t accidentally rip them out when you’re weeding -this has happened to me a number of times! and it’s terrible. It’s probably a good idea to flag them in some way for the first year.).
They need full to part sun, and they like a medium-wet to medium-dry soil, but the corms (very similar to bulbs) don’t want to be in a wet spot in winter. I would suggest planting 5-10 (or more!) every year to keep up your numbers because I have heard that voles love to eat these corms. So annually adding to your meadow blazing stars might be a good idea. In the right place, and if you don’t have too many voles, blazing stars (the Liatris genus in general) can live for decades.
If you’re looking to extend your liatris season (or live in the east), try Liatris aspera, or rough blazing star. These are also attractive to monarchs (although not quite as attractive as meadow blazing star), they bloom earlier in the summer, and are a bit shorter.
And of course my number one piece of advice is to plant them quite close to where you like to sit. Even if you think it’s an odd place for a tall plant, they have really attractive and interesting foliage as they grow in spring, and I bet you’ll grow to love having them and the monarchs so close by.
Today is the last day of National Pollinator Week, designated 13 years ago to raise awareness about the urgent issue of declining pollinators. Most of the usual parades, speeches, and balloon drops were canceled this year, but at my house, the week was marked by the blooming of common milkweed (Asclepias syriaca). Common milkweed has beautiful flowers, and smells as amazing as any orchid, but what it is really known for is being the most eaten milkweed of monarch butterfly caterpillars (Danaus plexippusplexippus). (Over 90% of monarchs choose to lay their eggs on common milkweed.)
The Migratory Monarch
Monarchs are part of a truly astonishing natural phenomena: a multi-generational, continental migration. North from Mexico in March, monarchs search out milkweed and lay the year’s first generation of eggs in Texas. The new butterflies continue migrating north, reaching throughout the Eastern United States and into Canada by early June. This is their summer breeding area, and they search out milkweed and lay the second generation of eggs. The third generation is typically laid in July, and the fourth generation in August. These late summer butterflies, make the long journey back to Mexico, where they overwinter in a small number of colonies (this last winter there were 11 colonies), in select Oyamel fir (Abies religiosa) forests , until the spring warms up, milkweed begins to grow, and they begin their northern migration again.
Because Monarchs overwinter in colonies, it allows researchers to measure their population size. They measure the density of monarchs on the fir trees and the hectares (1 hectare = 2.4 acres) of fir trees covered in butterflies. They’ve been using this methodology since the mid-nineties, and are able to reach a very good estimate of how many Monarchs have returned, and how the population is faring.
What we have seen over the last 30 years, is that monarch butterfly populations have declined by over 80%. From an average of 9.3 hectares (22.9 acres) in the 1990s, to 5.8 hectares (14.3 acres) in the aughts, to 2.8 hectares (6.9 acres) in the last decade. The lowest point for the population was reached in the winter of 2013-2014, with the population occupying just .67 hectares (1.6 acres) of forest, translating to something like 33 to 43 million butterflies. This frighteningly low population drew attention. In 2014, the Fish and Wildlife Service was petitioned to list the monarch butterfly as endangered (a decision on this is now due in December of 2020), and the Obama administration set out a presidential memorandum supporting pollinator and monarch habitat restoration and the planting of milkweed.
Over the last decade, it has become increasingly apparent that a main driver of the monarch’s decline is loss of milkweed due to agricultural expansion, and the Midwest’s wholesale adoption of herbicide resistant corn and soybeans. If we go back to the beginning of the century, we see that, at the same time as the monarch population was dropping, their food source, milkweed, was also in a steep decline. Starting in the 90s, the adoption of herbicide resistant crops (Round-Up Ready corn, soy, etc.), enabled farmers to achieve much tighter control of weeds. For example, in Iowa in 1999, common milkweed was detected in 51% of corn and soybean fields. But over the next decade, with increasing adoption of herbicide resistant crops, one study showed that, from 1999 to 2009, agricultural milkweed was reduced by 97%, reaching 99% elimination by 2013. Another study in Iowa, from the same time period found 100% elimination of milkweed from monitored fields, but no matter, the reality is the same: by some recent date, agricultural milkweed was eliminated throughout the Midwest.
The land area this represents is vast. At this point, over 90% of corn and soy planted in the United States is herbicide resistant, and so the total land in herbicide resistant crops comes to about 66 million hectares (scientists and their metric system!;)), or more than 163 million acres. To put this in perspective, Iowa is 35.7 million acres. Minnesota is 51.2 million acres. Illinois is 27 million acres. And then there’s still 50 million more acres of corn and soy! Land that was once monarch habitat has been reduced to a milkweed and flower desert. And so how many milkweeds are we talking about here? It’s estimated that this agricultural conversion translates to a loss of 850 million milkweed stems.
A conservation goal for the monarch population is that they reach an average overwintering population size to occupy 6 hectares of forest in Mexico. At this level, research suggests the population would have resilience against extreme weather events, and reduce their chances of nearing extinction by 50%. To reach this solid number of monarchs, we will need a correspondingly respectable number of milkweeds.
Unfortunately, by some super twisted twist of fate, it turns out that the low density, agricultural milkweed was actually the most productive milkweed, in terms of producing monarch butterflies, historically averaging 3.9 more monarch eggs than other milkweeds on the landscape. So to replace it, we will actually need to plant an estimated 1.3 to 1.6 billion milkweeds to make up for its loss. What?!! What the! GAhhh!! Ok, don’t freak out. We can do this, and people have been doing this. Researchers have been looking at just how this can get done. What’s life without a few big goals, right?
“The main finding of our study is that an all-hands-on-deck approach could be essential to restoring the massive amounts of milkweeds needed to make the monarch population healthy again.”
Wayne Thogmartin, U.S. Geologic Survey researcher
Conservation Reserve Program land (CRP)
marginal agricultural land converted to the Conservation Reserve Program
governmentally protected grasslands
roadside rights of way
powerline and rail lines
urban and suburban areas
A great paper from 2017, “Restoring monarch butterfly habitat in the Midwestern US: ‘all hands on deck’ ” by Wayne Thogmartin et al., demonstrates that the “all hands on deck” approach would be able to meet the milkweed needed to support a 6 hectare monarch population, but with a big caveat. It would mean looking to the agricultural sector to move 1/2 of the current marginal crop land into the Conservation Reserve Program, or a similar set-aside status. Given current government subsidy programs, crop insurance, and ethanol mandates, planting marginal land in row crops is still economically incentivized, and so marginal land entering a conservation-like status is not a certainty. But the 2018 farm bill did provide for an additional 3 million acres to be moved into the CRP program (equivalent to a bit less than a quarter of marginal crop land), so although it remains a large task, it looks like things can still move in the right direction.
Ask not what milkweed can do for you. Ask what you can do for milkweed.
But what are they asking of us, the urban/suburban, gardener/gardening club types, native plant enthusiast/maniacs? Well, they separate different levels of urban intensity with different expectations of stems of milkweed per acre, but on average for an urban/suburban area, in their highest level participation scenario, they are anticipating 3 milkweed stems per acre. My first reaction was to think they were certainly asking too little, but then I did the math for my town. My little 25,000 person town covers 10,580 acres, so that’s going to be about 32,000 milkweed stems. That sounds totally daunting, but lucky for us, with milkweed, one plant, left to it’s own devices, will likely become at least 10 stems in a couple years (though it would be great if a botanist/horticulturalist could verify this line of thinking!), which would knock down the number we truly need to plant to about 3,200. And we could round up to 4,000, to account for any milkweed crop losses, no problem. That’s totally do-able, right? It’s a lot. It will take a big effort, but I think it’s totally do-able.
So, there is a large task ahead, especially for us in the Midwest, because the Midwest is where the huge losses occurred, and the Midwest is considered the monarch’s core breeding range. In fact, a stable isotope analysis has shown that, historically, the majority of overwintering monarchs came from the Midwestern corn belt.
Urban/suburban Gardeners! Let us pick up our trowels! In a world full of complicated questions, here is a simple question: Can you plant more milkweed? And more importantly, can you think of two neighbors and three or more friends that you can convince to plant common milkweed? Milkweed is needed not just in native plant enthusiasts’ yards, but in many yards, across the city, all the parks and empty lots, grocery store parking lots, along our city roadsides, in the medians, traffic circles, churches, libraries, every single school. Oh, the list goes On. Widespread, chemical free milkweed (and nectar flowers), in town. This is our job.
But we don’t have to plant milkweed alone. There are many organizations working to save monarchs and pollinators. And importantly, there is a wonderful organization helping to create partnerships and provide coordination for this huge, multifaceted conservation effort, the Monarch Joint Venture. If you feel like getting to work, finding a local group, planting some milkweed, planting some nectar plants for migration (can’t forget those!), their website is a great place to find resources or find a group to work with.