Have you seen a monarch butterfly in your garden yet? If you have, you are luckier than most. It’s late August and I am still waiting to see one flitting around my gardens and landing on my flowers.
Widespread loss of a plant called milkweed and extreme climate fluctuations have caused numbers to plummet. Cold, wet springs and extreme hot temperatures have taken their toll on the monarch population. Drought conditions and historic wildfires of the past few years have also decreased their numbers.
Monarchs have the most amazing migratory phenomenon in nature. Every autumn, millions of monarchs fly south and west from southern Canada and the United States, stopping at sites along the way to feed. Butterflies need warm temperatures and sunshine to acquire enough energy to fly. The process takes thousands of miles and spans three to four generations.
Most adult butterflies live only about a month, but the final generation lives about seven to eight months; the time required to make the flight from Canada and the U.S. to central Mexico. The final destination is the forests of the Mexican states of Michoacan and Mexico, where they spend the winter before the cycle begins anew.
To complete the migration to Mexico, butterflies need to lay their eggs on a specific plant: milkweed. Prolonged wet weather stops adults from finding mates and laying eggs for next year’s generation. Eggs, larvae and pupae develop more quickly in milder conditions. Temperatures above 95 degrees can be lethal for larvae. Once hatched, monarch larvae eat milkweed leaves as their first meal. Wet conditions prevent caterpillars from thriving. Chubby, zebra-striped monarch caterpillars gorge themselves on the plants’ milky alkaloid sap, which makes them poisonous to birds. Young monarchs rely on the milkweed for food. After seeing and smelling a plant, they come to it and test it. The female takes her front legs, which have chemical receptors, and scratches the leaf, tasting it with her feet to confirm it’s milkweed.
Milkweed is not a favorite of farmers, though. Once widespread throughout the U.S., the plant’s range has fallen considerably due to herbicide use on corn and soybean fields. Millions of acres of land are being lost that would support monarchs, either by farmers converting dormant land for crop use, or the use of herbicides and mowing. Research has shown that butterflies often frequent corn and soybean fields, where milkweed plants used to be plentiful. The smaller the population gets, the more vulnerable it becomes.
It may be tough to change the weather, but there are other ways to help the butterflies.
Create butterfly habitat by planting milkweed plants. Look for a sunny place away from pets and traffic where the butterflies can spot the plant from above. Start from seed to avoid systemic pesticides that some growers apply. To encourage leafy growth, cut milkweeds back after they bloom. Adult monarchs need nectar, so entice them with plantings of flat, upward-facing flowers. Plant seeds of the milkweed plant indoors or direct sow outside after danger of frost has passed and the soil has warmed. If the appearance of the plant is too weedy for your taste, grow milkweed plants in a hidden but sunny corner or at the back of a border.
The native or wild milkweed plant may reach two-six feet. Leaves grow from a thick stalk and are large and green, taking on a reddish color as the plant matures. At first the leaves are waxy, pointed and dark green, later dropping from the stem and allowing the milky substance to exude from the growing milkweed. Stems become hollow and hairy as the plant matures. The milkweed flower is pink to purple to orange and blooms from June to August.
As a second choice, there also are milkweeds or swamp milkweeds available at garden centers that bloom white, pink, yellow or orange. The white and pink prefer moist soil and are quite tall. The yellow and orange bloomers are shorter and prefer drier soils. Seeds of all milkweeds are contained in an attractive pod that bursts and sends seeds drifting through the air, borne by wind, so you may want to remove seed pods or allow them to reseed naturally.
You can do your part. Plant milkweed in your backyard to ensure the future of the monarchs. My grandkids will thank you for it.
Nancy Helms is an Anoka County Master Gardener.