As we enter peak monarch butterfly season, here is the latest on the status of these majestic and vulnerable insects.
Monarch butterflies migrate north in a relay race, with three to four generations successively laying eggs and passing the baton to their offspring. In Maine, you will start to see the final generation in late June, but abundance peaks in mid-August. The caterpillars that you will find munching on your milkweed are part of the ‘super generation.’ Not only are these butterflies significantly larger than their predecessors, but they migrate the entire way south to Mexico. This is the same migration route that multiple generations took earlier in the year! It is hard to believe that such a delicate creature can make such a terrific journey.
If you feel like you’ve seen less monarchs this year, you may be right. The Monarch Butterfly Fund, which monitors the population status of these butterflies, notes that overwintering monarch populations have decreased by more than half since last year. This also marks the second-lowest population ever reported. To reach a population stabilization threshold, this population must increase by sixfold! In December 2023, monarch butterflies were listed as Vulnerable instead of Endangered. They will be reevaluated for the Endangered Species Act in December 2024.
Thankfully, there is a way to help our monarchs right now. The easiest way to do so is to plant their caterpillar host plant, milkweed. We sell three species of milkweed in our Native Plants Store, covering all ranges of habitat types—we have a plant for any yard!
Butterfly Milkweed (Asclepias tuberosa) is a great choice for a dry site. The plant rarely grows taller than three feet, and it produces beautiful orange flowers, a rare color for Maine native plants. Swamp Milkweed (Asclepias incarnata) is quite the opposite. Aptly named, it prefers moist to wet soils. These plants can reach up to five feet tall, and the flowers bloom pink. Our final species, Common Milkweed (Asclepias syriaca), is somewhere in between the former two ranges. This plant has larger leaves with plenty of surface area for caterpillars to munch.
All three of these species thrive best in full sun. In partial sun, they may not flower, but this is not a requirement to feed our monarch caterpillars! If you are looking to maximize caterpillar numbers, this 2018 study found that monarch females seemed to like Swamp Milkweed the best.
You can purchase these milkweeds at our Native Plants Store, where we also sell goldenrods, asters, Joe-Pye Weed, and many more wildflowers that provide nectar for monarchs and other butterflies. We’re also offering a special “Monarch Bundle.” For $45, you get five wildflowers that provide a source of nectar for adult butterflies: Common Milkweed, Swamp Milkweed, Butterfly Milkweed, Smooth Blue Aster, and Silverrod.
You still have time to bring the monarchs to your yard! Order online now and pick up your plants at Gilsland Farm or Fields Pond on select days. We have hundreds of milkweed plants looking for homes. To give monarchs the best chance, help us distribute these host plants to support our populations when they need it the most.
