Milkweeds (and Monarchs)


Gail in the milkweed container garden.



Monarch butterfly visiting a Cajun Prairie Few-Flowered (Red) Milkweed



Pollinator bees on Cajun Prairie Butterflyweed

While there are some 70 kinds of milkweeds in North America, only a dozen are found in south Louisiana, with 8 of these in the Cajun Prairie grasslands—several other species are found in the marsh along the coast or in the gallery forests. A commercially grown exotic species, Asclepias curassavica (Scarlet, Blood, Brazilian, Tropical or Mexican milkweed), can be purchased even at local big box stores when they are available—however, they do not like our winters and may die or die back and not be up and growing when the Monarchs arrive in April. So let’s talk natives and not worry about winters. Our natives die back to the ground in winter—they can also be mowed twice a year to stimulate new growth, blooming and fresh food for caterpillars/larvae of our Monarchs. The native species are up and readily available for Monarchs in the spring as they are co-evolutionarily timed to appear synchronously with the arrival of the butterflies.

Cajun Prairie species:

*Asclepias amplexicaulis      Claspingleaf (Blunt-leaf) milkweed
*Asclepias humistrata            Coastal milkweed
Asclepias lanceolata                Fewflowered (Red) milkweed
Asclepias longifolia                 Longleaf milkweed
Asclepias obovata                    Pineland milkweed
Asclepias perennis                  Aquatic (Shore) milkweed
Asclepias tuberosa                   Butterflyweed
*Asclepias variegata               White (Redring) milkweed
Asclepias verticillata              Whorled milkweed
Asclepias viridiflora               Green Comet milkweed
Asclepias viridis                      Green (Antelopehorn) milkweed

*Not found in the open prairies and marshes, but in adjacent forests and along the coast in sandy areas—these areas are within the Cajun Prairie ecosystem.

Milkweed distributions for the United States are provided at: .

A good guide to the milkweeds is available as a PDF from Texas Parks and Wildlife: .

Milkweeds have a great history. They were used as medicinals; their silk was used in a variety of ways; they are tremendous ornamentals; and they are host to a wide variety of organisms, most notably the Monarch and Queen butterflies.

Growing our native milkweeds has been difficult, but we at the Cajun Prairie Habitat Preservation Society have figured out how to do this with good success. At the Cajun Prairie Gardens, I have grown plants from seeds for the last 4 years with good success. The plants were then transplanted into the soil in my gardens, where they grew well and are now in good health and host Monarch larvae. I suggest that you do as I did and grow several species of milkweeds in your yard and garden—yes they can be grown along with your vegetables, but not if you use pesticides—it is then best to not grow milkweeds and invite Monarchs into a deadly zone, where the larvae will surely die.

My article on growing milkweeds is available from me as seen on the Coastal Prairie Partnership website: .
An excellent pdf file on growing milkweeds can be downloaded at the Xerces Website: .

The loss of Monarchs is coincident and correlated with the loss of pollinators and what is called ‘colony collapse disorder’ in honeybees. The loss of native plants/habitat by the intensive use of herbicides, fungicides, insecticides, and other biocides in general is further complicated by the introduction of genetically modified organisms (GMOs), e.g., Roundup-ready crops like corn, soybeans and rice, where the use of herbicides is exponentially increased. Add to this the use of Roundup essentially as a defoliate in wheat at harvest time and the use of Atrazine, the second most commonly used herbicide and another endocrine disruptor. This has led to a new paradigm in agriculture. The development of the corn-based ethanol production has exacerbated the development of ordinarily unused habitat (wildscapes) with milkweeds and the overall increase in cropland. The new agricultural paradigm and the growing urbanization of the Cajun Prairie (Midwestern and Texas coastal prairies) are collectively threatening the survival of both the milkweeds and the Monarchs. Thus, opening our minds to the plight of the milkweeds and Monarchs is a prelude to the recognition of the dire straits that nature itself has slid into. We must act locally in order to alter the global changes that are likely to fall upon us.

We are currently changing wildscape habitat (6,000 acres per day) that minimally has weedy milkweeds into lawn, which provides no milkweeds at all. The opening of our lawns to milkweeds companioned with the abstinence from pesticide use, including neonicotinoids, will make these lawns home to the milkweeds and the Monarchs that will follow. We can install beautiful milkweeds in our lawns and create habitat for Monarchs and hundreds of species of bees and other insects and birds.

In Texas, environmental and educational organizations are teaming up with MonarchWatch to carry out a literal crusade (Bring Back the Monarchs: ).

Doris Durbin Heard recently reported that the Asclepias tuberosa (Butterflyweed or Butterfly milkweed), the strikingly beautiful red-orange-yellow emblem of the prairie, was selected to be the ‘2014 Plant of the Year of the Garden Club of America’ in her note on page 15 in the June-July issue of the Garden Club magazine.

In Louisiana, the movement is beginning. Wendy Caldwell and Karen Oberhauser presented an article on Monarchs and milkweeds and promoted their preservation and restoration through the Monarch Joint Venture, a U. S. Forest Service effort, in the Louisiana Wildlife Insider, an online publication with beautiful illustrations available from the Louisiana Department of Wildlife and Fisheries ( ).

Linda Auld, the Bug Lady, has provided thousands of seeds of the Brazilian milkweed and some native milkweeds for growing Monarchs. She has recently accelerated her effort with Project Monarch—an effort to promote milkweed and Monarch preservation by growing butterfly gardens.

For general milkweed gardening, Pat Sutton in her article at: discusses planting milkweeds from your region.

Susanne Dingwell also writes at her page a wonderful piece on planting native milkweeds at and provides some wonderful photographs.

The goal is to replace lawn with milkweeds and create habitat for Monarchs—every town, home, business and school should be involved. It is not necessary to replace even a large piece of lawn, just a few square feet for a start. We can join them—not by paying dues or going to meetings—by planting habitat in our yards.

What is Monarch habitat?

Monarch habitat includes:
1. milkweeds, preferably native species from the Cajun Prairie, for larval food—enough to feed at least a handful of larvae.
2. nectar plants for adult food—not only do the milkweeds serve as nectar plants but any number of other flowering plants will do, including sunflowers, asters, zinnias, lantana, buddleia, daylilies, and many more. An emphasis on growing plants that bloom profusely in October and November is essential as these will provide nectar for Monarchs migrating south to Mexico. Milkweeds are essential for the Spring migration in March, April and May.
3. no pesticides—the use of glyphosates (including Roundup), Atrazine and agent orange (a mixture of equal parts 2,4,5-T and 2,4-D) kills milkweeds. Both of these are also endocrine disruptors—possibly the most dangerous factors currently affecting the health of humans on the planet.

Again the latter 2 aspects of habitat are rather easy to do, but the first requires some knowledge and sensitivity. The life cycle of the Monarch is intimately tied to milkweeds—without them literally the Monarchs disappear, forever, and therein is the problem that we can possibly solve.

Gail and I did a talk for the Houston Arboretum (Native Plant Society of Texas: Houston Chapter) talk on April 16, 2015:
* PowerPoint < >.This powerpoint contains pictures of the Cajun Prairie Gardens and the milkweeds of the Cajun Prairie.
* Video:

Barbara Keller-Willy presents Milkweed: A Dinner for Butterfly Royalty to the Houston Chapter of the Native Prairies Association of Texas on February 25, 2015: .

Marc Pastorek’s comments on growing milkweeds: .

Doug Tallamy’s (author of Bringing Nature Home) talk on natural landscaping:

Doug’s biodiversity talk: —this is just excellent.
Doug Tallamy 2015 talk for Wild Ones:

Doug’s emphasis is to protect nature in order to take care of birds. He notes that many people put out seeds for birds and celebrate their role in saving the songbirds; however, they totally ignore the 800 pound gorilla in the room—nestlings require insects as their food. The same half measure of providing nectar plants for butterflies and ignoring host plants for caterpillars applies here. Taking care of songbirds means providing lots of habitat for insects—as a single nestling may require more than a thousand insects, e. g., caterpillars, during development. Milkweeds and many other native plants, including many trees, are vital in this role as they host the very insects that the birds need.

A lot of recent press indicts a protozoan parasite for killing Monarchs. My friend Roy McLaughlin who studied under Professor Richard R. Kudo—author of Handbook of Protozoology ( )–described the now concerning, protozoan parasite of Monarchs in this article:
McLaughlin, R.E. and J. Myers. 1970. “Ophryocystis elektroscirrha sp.n., a neogregarine pathogen of the monarch butterfly, Danaus plexippus (L.), and the Florida queen butterfly, Danaus gilippus berenice Cramer.” Journal of Protozoology 17 (1970): 300-305. (original article). Read more about this protist at this website:

This protozoan (protist) is found on milkweeds, where larval Monarchs ingest them and then succumb to these parasites. Overwintering protists can be hypothetically eliminated by cutting back the milkweeds that are contaminated. Of course, burning the prairie milkweeds eliminates the majority of these protists.

Milkweeds and their Monarchs are emblematic of the prairies, not only in symbolization but also in their disappearances. As the prairies disappear, the milkweeds, Monarchs and thousands of other species literally disappear, including many of the major pollinators. Growing a prairie is a great way to join the national movement to save the pollinators. The best way to begin is to focus on the Monarch and grow milkweeds and other nectar plants that Monarch’s use—their wide variety of nectar hosts are common native and some exotic plants that are also used by many other pollinators.

Here is a recent note by James Trager (March 1, 2016) regarding Monarch oviposition in the Midwest:

James C. Trager Mar 1, 2016

There is a bit of confusion about monarch oviposition (egg-laying) and feeding preferences. Common milkweed is the primary food of Midwestern monarch caterpillars because it is by far the most abundant and evenly distributed species, not because it is the most favored by the insect. Apparently, monarchs will lay eggs on just about any milkweed (genera Asclepias and Cynanchum), but in side by side comparisons of the most most common species in central USA, they prefer swamp milkweed (A. incarnata) above all, then common milkweed (A. syriaca) = showy milkweed (A. speciosa, of the western half of the region) > orange milkweed (A. tuberosa) > vine milkweed (C. laeve). Egg-laying females are highly attracted to tropical milkweed (A. curassavica), native to the American Tropics, and often planted in gardens, but this highly toxic milkweed actually stunts monarchs’ growth some (lower body weight and smaller relative wingspan compared to monarchs reared on other milkweeds), and there are indications there may be other detrimental effects to caterpillars growing on dense plantings of these milkweed, such as increased likelihood of disease transmission among the high populations of caterpillars that can form on them.


Additional note (031116):

Monarch numbers are apparently up as there were 4 hectares of trees with Monarchs this winter. Let’s hope that this huge low during the early part of March has not hurt these numbers too much. Much of northern Louisiana is under water.

Posted by M. F. Vidrine 011116 (



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