Last Saturday, I spent the afternoon reading picture books and talking about monarch butterflies with my granddaughters. (One we read was called Home Is Calling by Katherine Pryor, about the migration patterns of monarch butterflies. It’s a beautiful book filled with gorgeous illustrations and factual information woven together in lilting prose. The teacher in me was impressed!) Ironically, the very next day I happened upon a report from the World Wildlife Fund in Mexico stating that the eastern monarch population in central Mexico has nearly doubled this year, occupying twice as much forest land as last year. According to researchers' estimates, that means that approximately 28 million monarch butterflies are currently overwintering on about four acres of forest. (A number to celebrate, but nowhere near numbers from the late 90s when butterflies covered over 45 acres of forest.) While the number of butterflies in Mexico may not seem pertinent to us here in the United States, it actually is encouraging news for us too. It could be a sign that we can still save this iconic species from extinction – if we understand them and what they need to survive.
Monarch butterflies are the only known species to have a two-way migration pattern. To get to their overwintering habitat, monarch butterflies have to complete a remarkable two-month, 3000-mile journey beginning either in Canada or the northern most portions of the United States, crossing through the length of the United States and ending up in central Mexico. Throughout their migration pattern, monarchs travel 50 to 100 miles a day, relying on the availability of critical habitats to survive. Besides the need for energy-producing nectar, finding access to forest land is one of the monarchs’ primary challenges as they migrate south. Healthy stands of trees help to protect the travelers from wind, rain and evening temperature shifts. Without places to settle in and rest along the way, even fewer monarchs would complete the trip. Researchers have found that only 1 in 100 tagged monarchs survive the trip, which gives some insight into how difficult the trip is.
Once the butterflies arrive at their winter habitat, they cluster together on the trunks, branches and needles of pine and fir trees. They search for nectar in late blooming flowers and seek water for hydration but have no need for milkweed since they don’t lay eggs.
As spring approaches, monarchs begin to leave Mexico and start their return to their summer breeding grounds. Those 28 million butterflies currently resting in Mexico will soon begin a 600-mile journey north, where they will stop and lay their eggs on available milkweed plants. Once eggs are laid, the monarchs’ eighth month life cycle ends, but the second generation of monarch butterflies continues the northward march. The migration continues with 3 - 5 new generations of butterflies instinctively heading towards their “home” to complete nature’s cycle. Unlike their ancestors, the newly hatched monarchs will live only three to five weeks, just long enough to complete another leg of the journey, lay their eggs and die.
While they needed nectar rich flowers and healthy forests for their southern migration, monarchs’ needs change for the northern journey. On their way home, monarchs require nectar to eat and milkweed on which to lay their eggs and feed their offspring. Milkweed is absolutely essential, since it is the single host plant for monarch caterpillars.
As I read about milkweed, I was astounded to find out that there are 73 different species of milkweed native to the United States. Because of climate change, habitat destruction and the use of toxic pesticides, at least 43 of the species are listed as rare, threatened or endangered. The surviving thirty native milkweed varieties are scattered throughout the ecoregions of the country. Unfortunately, large swaths of the plants are becoming increasingly difficult to find.
In the late 1990s, the Xerces Society along with the Mexican government recognized the threat that monarch butterflies and scores of other pollinators faced. They began a campaign to bring public awareness to the substantial possibility of extinction, and what that would mean for humans. A large factor of the campaign was, and still is, the push to plant monarch waystations filled with milkweed and other nectar producing plants, especially native plants along migratory routes.
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The campaign has certainly raised the public’s understanding. The popularity of planting for butterflies soared and customers began demanding milkweed plants to add to their gardens. Because of its bright orange blooms that attract a myriad of pollinators, its attractive foliage and tidy growth habit, Butterfly Milkweed, Ascelpias tuberosa, quickly became the milkweed of choice. The vibrant orange color began popping up everywhere, especially in gardens that had full sun and average, well-drained soil that would support the plant’s deep taproot.
While Butterfly Milkweed is an excellent choice for the monarch population, entomologists are learning that to better protect the species, we need to offer a variety of types of milkweeds in our gardens. There are currently nine species of milkweed available in most garden centers on which monarchs will lay their eggs. Female monarchs don’t seem to have a distinct preference, but their choices do seem to change according to the health of the plant and the timing of the season. Having several options available, especially ones that are at their peaks at different times, can potentially attract and sustain several generations of monarchs.
Early spring is an ideal time to plant milkweed plants. (Starting milkweed with seeds is typically more successful in the fall.) The cooler temperatures and abundant rainfall allow the roots to settle into the ground and begin growing before harsh summer conditions arrive. By planting large clumps of a variety of milkweed species and other nectar rich natives in the early spring, you are allowing generations of monarchs to complete their natural life cycle. However, with milkweeds, just like other plants, choosing the right plant for the right place is critical for success. To help you decide which varieties are right for you, we’ve put together a printable guide to the eight common species. Just click here to access it.
Join us next week as the talented designers at Embassy Landscape Group share their ideas on how to incorporate your new, native plants into a beautiful, sustainable sanctuary for the butterflies and for you.
We all hope to see you then.
