Monarchs and Milkweed
by Karen Weiland, Advanced Master Gardener
Lite and airy butterflies flitting about are a nice addition to any garden area. To attract butterflies to your garden, it’s important to understand what it is that they most want out of life which is food, a place to sun themselves out of the wind and a source of water.
In recent times the Monarch butterfly population has declined. Mowing their habitats and the use of pesticides has been blamed as the culprits. While butterfly nectar plants are usually in good supply, it’s the needs of the Monarch larva that some folks may be unaware of.
Monarch butterflies depend on milkweed to complete their life cycle. Female butterflies lay eggs on plants within the milkweed family (Asclepiadaceae). In the larval or caterpillar stage, a Monarch feeds on the milkweed leaves. When it is ready to pupate, the caterpillar forms a chrysalis (attached to the milkweed) in which it grows into a butterfly.
Milkweeds contain toxic steroids, known as cardenolides, which have a bitter taste. Monarchs store the cardenolides in their bodies when they eat the milkweed as a caterpillar. When the Monarch emerges as an adult, it still has the steroid in its body. This is a form of defense for them against predators that try to eat them. Predators soon learn that the Monarchs do not make a tasty meal.
The common milkweed will grow to about three feet or better, produces a globe-like flower cluster and will bloom in the summer. This type typically grows in zones 3-9. It likes full sun and well-drained soil. When the stem or leaves of milkweed are damaged, a white, milk-like substance will ooze out which gives the plant its name. This white sap is toxic to some degree to humans and animals., but not all milkweed species are equally toxic. Common milkweed is only slightly toxic to humans and humans have been known to eat common milkweed. I certainly don’t understand why someone would want to eat milkweed when there is peanut butter pie!
So what can you do to help the Monarch population? Plant milkweed, do not use or be extremely careful with the use of pesticides and plant lots of nectar plants for the adults, providing a continuous supply from spring through fall.
Butterfly magnet plants would include: common milkweed (Asclepias syriaca) often grows along roadsides and in fields, butterfly weed (Asclepias tuberosa) has showy, bright orange flowers and is native to Indiana and swamp or marsh milkweed (Asclepias incarnata) found near lakes, ponds and marshes, also native to Indiana. The monarchwatch.org website has numerous listings with pictures of milkweed.
Some examples of nectar rich plants are: garden phlox (Phlox paniculata) native to Indiana, blanket flower (Gaillardia), goldenrod (Solidago canadensis), joe pye weed (Eupatorium purpureum), blazing star (Liatris spicata), tickseed (Coreopsis verticillata), aromatic aster (Symphyotrichum oblongifolium), native to Indiana and purple coneflower (Echinacea purpurea) native to Indiana.
The nice thing about planting native plants is that they are adapted to our growing conditions and therefore will grow well without a lot of pampering as long as you place them where their light and moisture requirements are met.
Do your part to help the Monarch and plant some milkweed in your garden.
As always, Happy Gardening!
More information about gardening and related subjects is available at The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben Co.
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