The Incredible Journey of the Monarch Butterfly

It sounds like a children’s story. A frail, eensy-weensy creature makes an epic journey, dodging giant predators, finally arriving at the promised land. It sounds impossible, but it really happens.

Consider – if you were a tiny creature no bigger than four inches and weighing no more than a gram, sporting bright orange and black wings with polka dots (you have to give them style points), you’d find it hard to hide from predators. That’s what makes the thousands of miles tiny Monarch butterflies travel so astounding.

A Monarch butterfly rests on a Swamp Milkweed plant.

Monarchs just don’t believe they can’t do it, so they do. Maybe it’s those polka dots? In the fall, they fly high, so very high they’ve been spotted from airplanes, and go for the perfect vacation spot. So what if it’s 3,000 miles away? Monarchs go for the good times.

Exhausted by their two-month long journey, Monarchs just want to find a nice Oyamel fir tree and settle down for a long winter’s nap. They deserve it. So would you, if you had, all by yourself, walked non-stop all the way from Canada to Mexico! West of the Rockies, Monarchs flock to San Diego, Monterey and Santa Cruz from October through March.

They’re tiny, but they have the heart of a lion, at least. In spring, Monarchs leave their cozy winter homes and start their long journeys back, perhaps to Canada (in the west, they head back to the Rockies or North to Oregon through to Canada). It can take five generations to reach Canada, but it’s warm weather, no hurry.

Taken in one of three pollinator gardens located on Environmental Concerns’s campus, these Monarch butterflies are drinking nectar from the Seaside goldenrod.

We, who live in the mid-Atlantic region, see Monarchs on their migrations; the little adventurers aren’t planning to stay here. In March, the Monarchs who made the incredible journey all the way to their Oyamel tree vacation start back north, stopping to breed and lay eggs in the southern states. Then, they’re done; they just haven’t any more in them, so they leave the next long journey to their children.

After hatching from its egg, a Monarch caterpillar emerges to eat the Milkweed leaves.

The second generation takes up the quest. By May, they’ve eaten their fill as a caterpillar (larvae), pupated (the miracle where the caterpillar becomes a butterfly), and they, too, start flying hard. This generation flies further north, stopping to breed another generation anywhere it makes sense. Third, fourth even fifth generations emerge from their chrysalis from May to August, all flying north and breeding where they can.

Then…that final generation, the children of August, take off for the Oyamel fir trees in Mexico. If they have to fly 3,400 miles, that’s what they do.

Nobody can say how long Monarchs have been making this journey, but there’s a deep worry that we can say when it ends. Global warming means the weather is changing in the Monarch’s winter Shangri-la, which is also shrinking due to development and insecticides; currently it is less than half what it was in the 1970s. The new warmer world has led to storms and cold that make their survival problematic each year. Luckily, the populations have managed to rebound each time, but concurrent development in the Monarch’s summer digs isn’t helping.

Fortunately, the word is out in many places, and gardeners are striving to plant the milkweeds the little adventurers need. Milkweeds used to be as common as…weeds, so the Monarch’s dependence on them as fodder for their young (caterpillars) makes sense. But, as more and more dream homes and fast food joints spring up, fewer and fewer milkweeds are allowed to grow. This is a shame, not only for Monarchs, because, while the plant’s toxicity to animals led to “weed” in its name, they really are lovely plants, often with striking blooms that attract all sorts of bees and butterflies to nectar on them. The loss of the milkweeds is a loss for all.

Want to help the intrepid voyagers? Here’s a primer. It starts with maintaining a no-pesticides yard, but there’s so much more. Plant many native blooming plants, from trees to flower beds, to achieve full season bloom to feed the Monarchs on the move. And plant milkweeds.

While there are more than 200 species of milkweed in the USA, only a dozen or so are native here in Maryland. They’re poisonous, of course, but Monarchs are immune to the toxins. Those toxins actually are a large part of their ability to travel so far, as the butterflies are poisonous to those who try to eat them. Birds, toads, and other would-be predators quickly learn not to eat the brightly colored butterflies (they’re poisonous, but not deadly. Predators will get violently sick). It’s such a good ploy that Viceroy butterflies have evolved to look as much like them as possible. Viceroys aren’t poisonous, but any bird who’s eaten a Monarch will avoid them, too.

Monarchs can use any milkweed to achieve their poisonous state, but they vastly prefer Swamp Milkweed, Asclepias incarnata, and Common Milkweed, Asclepias syriaca. Both are perennials, as are all milkweeds, which means they come back year after year. It’s actually the same plant, similar to a tree except that only the roots winter over, not the whole plant.

Seeds are the easiest method for growing these plants. You can go through the process of scarifying them (using cold to help break the seed coat) and growing them under seed lights until you plant them outdoors, but by far the easiest method is to collect local seeds and plant them – in the fall, when the wind would naturally blow them to the new spot – where you’d like them to grow. Press them gently into moist ground, perhaps walk gently upon them to create a good seed-to-ground contact, just as you would grass seed.

Come spring it’s likely you’ll see some sprouting. They’ll be tiny, but that’s okay. They all start out that way. They won’t get very big the first summer, but don’t give up on them. It’s just their way. Most perennials do exactly the same thing – stay small the first year and focus on growing roots, which are the only part of the plant that will winter over.

The next year you’ll find they’re back; bigger, and they continue to get bigger and bigger. They’re not babies anymore and they’re showing off. They may even bloom. That’s great – they will certainly bloom the third year and every year beyond that – but we don’t grow these plants for the bloom, pretty as it is. We grow them for the leaves. The toxic leaves make a Monarch such an unpleasant and memorable experience for predators.

Starting from seed or lucky enough to have potted plants to start out, do your best to make sure there are quite a few milkweeds in a grouping. Experts recommend a clump several feet around. These are those “very hungry caterpillars” you’ve undoubtedly heard of. They’ll eat lots and lots of milkweed before they trundle off to pupate. The large clump will also make it obvious to a high-flying Monarch that there’s milkweed here.

While Milkweed is an almost ideal plant for gardeners of all stripes, it’s difficult to split it as you would other perennials. They tend to have strong tap roots. You can, when they’re very young, lift them gently and spread them out a little, but once they’re a year old it’s almost impossible to split or move them without killing them. If you buy potted plants, they will seed out in a few years.

Many gardeners are charmed by the eye-popping summer bloom of one of the milkweeds, “Butterfly Weed,” a.k.a. Asclepias tuberosa. The orange flowers draw every sort of butterfly imaginable, as well as hummingbirds, to nectar on the flowers. This plant is often available in native plant nurseries due to its popularity. It likes sun and relatively dry soil, so if this sounds like your yard, put it on your list for your garden.

Other milkweeds’ flowers are less astounding but still very pretty and attractive to butterflies of all sorts. Generally pink, they brighten gardens and wild places from Florida to Maine. Choose your variety based on conditions in your yard. For sunny, dry areas, Common Milkweed (Asclepias syriaca), is a great choice if you don’t like, or want to compliment, the flamboyant orange flowers of Butterfly Weed; if you have sunny and wetter conditions, Swamp Milkweed (Asclepias incarnata) is your friend. There are even some that prefer shade; if that’s your yard, choose Poke Milkweed (Asclepias exaltata).

There are other milkweeds native here, but some are rare and/or endangered, so don’t expect to plant them. If you find them in your yard, celebrate! The Monarchs will, too. And leave them alone. These plants don’t transplant well, so if one has found its perfect home, wherever it is, leave it alone. Generations of Monarchs will thank you for your kindness.

Milkweeds are accustomed to having lots of plants all around them; they are often found in meadows, for example. This is great for the little caterpillars, who will leave the milkweed to find a good spot to pupate. If there’s a nearby shrub, it very likely will be the very spot for an eager-to-make-the-change caterpillar. Caterpillars won’t pupate on the plant they’ve been eating and they love shrub branches.

The milkweeds are strong and used to Monarch munching. Even if the caterpillars decimate your planting, the sturdy flora will be back strong next year, ready to get on with living.

Milkweeds, the “Asclepias” family, are versatile additions to any garden or “wild area.” Grow them to help your Monarch friends. To all the tiny high-flying Monarchs – journey well.

Maureen Rice is a Master Naturalist living and writing in Talbot County.

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