Where oh where have the Monarch butterflies gone? I heard this question many times this past summer. Mostly, it seems the weather was to blame, at least in New England. Butterflies need sun and warmth in order to fly, and they need to fly to locate Milkweed plants to lay their eggs. Their wings are like little solar chargers, soaking up the sun to fuel their flight. This year’s cold and rainy weather in New England provided few opportunities for female Monarchs to fly to areas containing Milkweed plants (Asclepias species), which is the only plant that Monarch butterfly caterpillars can use as a food source.
The good news is that this could be just a regional blip. According to Journey North, a project that documents Monarch numbers during their fall and spring migration, in the past week, Monarchs have been seen crossing into northern Mexico in numbers that have not been seen in years. Hopefully this means that although Monarchs were scarce in New England this year, the weather simply kept them away.
But the weather isn’t the only problem affecting Monarch populations. Illegal logging in the forested regions of central Mexico, where Monarchs make their winter home, has reduced the winter habitat available to those butterflies who survive the long flight south. And according to research at the University of Georgia, since 1976 the female-to-male ratio of Monarch butterflies shows a major decline east of the Rockies. Because females can lay up to 400 eggs over the course of their lifetime, any reduction in their numbers is troubling for population stability.
Researchers are not sure why female populations are declining, but as gardeners we can all help Monarch populations by planting Milkweeds in our yards and gardens to provide food for Monarch caterpillars. If you think they’re weedy looking, think again. There are several types of Milkweed that will grow in New England, and whatever your conditions, there’s a beautiful variety suitable for your garden.
Well-drained, sunny spot? Just perfect for the neon-orange Butterfly Weed (Asclepias tuberosa), shown below with our Farm Director “Speck”:
If your soil contains some moisture, Swamp Milkweed (Asclepias incarnata) is a good choice. It’s tolerant of drier soils, too. Besides being the sole food source for Monarch caterpillars, Milkweed flowers contain huge amounts of sweet nectar that all butterflies (not just Monarchs) love. Below, a Great Spangled Fritillary butterfly sips nectar from Swamp Milkweed flowers:
If you have a larger property with areas that you can let “go wild”, Common Milkweed (Asclepias syriaca) has gorgeous ball-shaped pink flowers with an intoxicating honey scent. Common Milkweed grows naturally in waste places and old fields in New England, so who knows, if you have an area that you can leave unmowed, it may just pop up on its own…
Although not native to New England, Scarlet Milkweed or Bloodflower (A. curassavica)is a worthwhile annual to include in flower beds and patio pots. Its flowers bloom in a striking red, orange and yellow:
The first year we planted Scarlet Milkweed in a container on our patio, almost immediately a Monarch butterfly found it and laid her eggs. To our delight, two of them hatched, and one climbed onto a nearby trellis to start its transformation into a butterfly:
Below is the chrysalis that eventually morphed into a brand new adult Monarch butterfly:
How do they do it?
Scientists and naturalists have always been fascinated by the complex life cycle of the Monarch butterfly, but new research published in Science magazine is showing just how these tiny creatures are able to navigate their way 2000 miles to the same small region of Mexican forest each fall to spend the winter. It turns out that Monarchs have a type of GPS navigation system and circadian clock built right into their antennae, which allows them to use the sun to guide their travel as well as to correctly adjust their direction based on the time of day. Amazing!
Remember, no Milkweed, no Monarchs. Let’s help these unique winged wonders survive for future generations to enjoy by growing Milkweeds anywhere we can!