Showy Milkweed (Asclepias speciosa)

I planted my milkweed research plot on June 21st.  Just one week later, on June 29th, I had 3 monarch eggs on my showy milkweed plants (and no eggs on any other milkweed species).  By July 2nd, a caterpillar had emerged.   It was so exciting to have those first monarchs to watch!  Look on the photo below for the larva's little black head on this showy milkweed.  The caterpillar has just emerged, and before starting its milkweed diet, it will turn around and eat its egg shell, which is directly in front of it.

Showy milkweed is closely related to common, has vigorous growth, but is not as invasive.  It, too, can grow to 5 feet tall, and also has long, thick hairy leaves.  My showy milkweed seemed to grow more horizontally than my common.  Below is a photo of a 2nd and a 5th instar caterpillar on showy milkweed.

Here are the 6 showy milkweed in my research plot on July 30th.

Common milkweed (Asclepias syriaca)

Common milkweed , the bane of farmers and bean walkers!  However, it is a staple in a monarch's diet, and in my research plot this summer, had the second highest count of monarchs, with 30 total: 19 eggs and 11 larva.  In the prairie, you can see how tall this milkweed will grow, if you notice there is another common milkweed over my left shoulder in this photo taken at Neal Smith National Wildlife Refuge.

This perenniel grows from deep rhizomes, so once it's established, I'll need to control its spread in my flower bed.  Here is a fifth instar preparing to form a chrysalis on August 15th.  Notice that the common milkweed's elliptic leaves are fuzzy, particularly on the underside.  

On August 16th, the caterpillar had formed a chrysalis.

When I approached the plant on August 30th, a monarch butterfly flew off the plant.  Usually adults emerge in the morning and it takes most of the day to inflate and dry its wings so it can fly. Notice the reddish fluid (called meconium) on the leaf below:  that is leftover metabolic waste that was expelled after the butterfly emerged.

Swamp Milkweed (Asclepias incarnata)

With our wet year, swamp milkweed flourished, which could be one reason why this species had the most monarch eggs and larva in my plot. They were also the only variety that bloomed the first year for me.  Here is swamp milkweed in my research plot with a 3rd instar monarch larva under one of the leaves.

Research was completed this summer by members of the Monarch Consortium to determine which type of milkweed attracted the most monarchs.  (Hopefully I'll be able to report about their findings in future blog posts.)  Every week, those of us with milkweed plots counted the number of eggs and larva on each of the 54 milkweed we planted.  We also took note of things like the condition of the milkweed, presence of spiders and aphids, and the amount of rain.  Of the 9 milkweed species in my plot, swamp milkweed was the species that had the most eggs and larva, with a total of 40 eggs and 17 larva counted throughout the summer.   Swamp milkweed are a tall, slender-leaved plant.  If you look closely at these swamp milkweed, you can see a 4th instar caterpillar on the end of a leaf, level with the 33" mark on the yardstick.

Milkweed

 

This is my milkweed plot at the end of the year, on October 10th.  After one summer in the ground, I thought it might be helpful to share my observations about each variety, even though I'm sure I'll be more milkweed savvy in a couple more years.

The  milkweed are around the outside of this garden with flowers and grasses on the inside.  Contrary to what I read online, rabbits do enjoy eating milkweed, so I had to put them inside a rabbit-proof fence.  Directly in the front (with the fence posts to support them) are the honeyvine milkweed (Cynanchum leave).  Going counterclockwise around the garden are: showy milkweed (Asclepius speciosa), whorled milkweed (Acslepias verticillata), prairie milkweed (Asclepias sullivanti), poke milkweed (Asclepias exaltata), common milkweed (Asclepias syriaca), swamp milkweed (Asclepias incarnata), tall green milkweed (Asclepias hirtella), and butterfly weed (Asclepias tuberosa).  

Part of the research I did with my plot, was to keep a weekly record of how many monarch eggs and larva each plant & variety had on it.  So, each week for the next 9 weeks I will be sharing my observations about a different variety of milkweed, beginning next week with the milkweed variety that totaled the most eggs and larva in my garden his year, Asclepias incarnata, or swamp milkweed.

Iowa Monarch Conservation Consortium

In an effort to enhance the monarch butterfly's habitat in rural and urban Iowa, a monarch consortium was created in 2015, led by Iowa State University.  Farmers, conservation organizations, state agencies, companies and ISU's College of Agriculture and Entomology belong to the consortium.  Iowa State is leading research to develop cost effective methods and coordinate resources, information and support. Go to the following website to learn more:

Monarch.ent.iastate.edu/

As part of the consortium, nine different varieties of milkweed were planted across the state to determine monarch preferences and establish cost-effective methods to maintain milkweed.  I planted my own research plot: