A milkweed by an other name …

What’s in a name? that which we call a rose
By any other name would smell as sweet;
– Juliet, Romeo and Juliet, Wiliam Shakespeare

A rose is a rose is a rose is a rose.
– Gertrude Stein, various

I started to get into a little tiffle on a post (since removed) on one of the insect ID groups in Facebook. The original poster was trying to ID a tight cluster of orange eggs on a leaf of a plant she identified as “milkweed vine.” One of the responders commented: “Milkweed vine? Not likely.” And then we were off.

What’s a “milkweed,” anyway?

Responding in a comment, the original poster specified that the plant was Morrenia odorata, an introduced, and invasive, vine in the Apocynaceae, the dogbane family. (Some authorities still list it under Asclepiadaceae, the milkweed family, which is now considered a sub-family, Asclepiadoideae, of Apocynaceae.) Its common names include latex plant, strangler vine, and, yes, milkweed vine.

The responder’s objection was that “Aclepias is milkweed.” Period. Final. Absolute declaration.

It’s not that simple.

Common names like “milkweed” have no authority. Many plants have “milkweed” as part of their common name, not just Asclepias species. Cynanchum laeve, a native vine in the same family as Morrenia and Asclepias, has a common name of climbing milkweed, among several others.

Noone can claim that only Asclepias species can be called “milkweed.” To insist so is, at best, dismissive. I would use stronger language. (I blocked the responder on Facebook to avoid future tiffles with them.)

Why plant ID matters for insect ID

Why did the original poster include the id of the plant in their requesting for identifying insect eggs? Because they understand that many insect species depend on different types of plants. Specialist insect-host associations are common in the co-evolutionary biochemical arms race between insect herbivores and their host plants.

Only five years ago, I didn’t have any knowledge of insect-host plant relationships. Marielle Anzelone (@NYCBotanist on Twitter – follow her!) clued me in on what was going on when I observed this in my backyard in May 2011:
Battus philenor, Pipevine Swallowtail
I recognized it as a swallowtail. Knowledge of the plant – Aristolochia tomentosa, wooly dutchman’s pipevine – id’d the butterfly as pipevine swallowtail, Papilo troilus. The caterpillars of this species feed only on plants in the Aristolochiaceae, the pipevine family, primarily – but not exclusively – Aristolochia species.

And so it is with “milkweeds” and their most famous herbivore, the caterpillars of monarch butterflies, Danaus plexippus.
Danaus plexxipus, Monarch, on Eupatoridelphus maculatus (Eupatorium maculatum), Spotted Joe Pye Weed
The butterflies nectar on a wide variety of flowers. Their caterpillars, however, are specialized feeders on plants in the Apocynaceae. While they are most commonly associated with Asclepias species, they have also been observed on Cynanchum and Apocynum species. They have even been observed on a few plants outside of this family.

So, when trying to identify insects, knowledge of plants, plant families, and their ecological associations is also important. Being pedantic about common names, not so much.

Related Content


Battus philenor, Pipevine Swallowtail, Butterflies and Moths of North America (BAMONA)
Battus philenor host plants, HOSTS: World’s Lepidopteran Hostplants Database
Danaus plexippus host plants, HOSTS: World’s Lepidopteran Hostplants Database
Aristolochia tomentosa Sims, woolly dutchman’s pipe, USDA PLANTS Database (Synonym: Isotrema tomentosa (Sims) Huber)
Isotrema tomentosum (Sims) H. Huber,  NY Flora Association Atlas (Does not list as present, let alone native, in NY)

Some recent and current blooms in my garden

Hemerocallis, Daylily, June 21, 2008
Hemerocallis, Daylily

Just some quick photos of plants recently or currently blooming in my garden. The first few were taken two weeks aga.


I’ve changed my feedburner feed to remove the merged feed of photos from my Flickr site. I sometimes upload scores or hundreds of photos at a time. Also, often those photos are of events that are of more local community and less general gardening interest. For both these reasons, I think that including my photos interferes with the main use of the feed: subscribing to updates to this blog.

Those of you who want to keep tabs on my updated photos can still do so. My Flickr photostream has its own feed, available in either RSS or Atom format. You can subscribe to my photos directly from there.


I don’t “collect” daylilies, at least not the way I try to collect Hosta or native plants. We inherited a few with the gardens when we bought the house. For that reason, I consider them to be “passalong” plants: dependable, sturdy, hardy, tolerant of neglect, vigorous, and so on. I gave away several clumps this Spring. I’ll have more to give away over time.

Hemerocallis, Daylily, June 21, 2008
Hemerocallis, Daylily

Native Plants

Ascelpias incarnata, Swamp Milkweed, June 21, 2008
Ascelpias incarnata, Swamp Milkweed

Echinacea pallida, Pale Coneflower, June 21, 2008. This photo was used to illustrate “Coneflowers: America’s Prairie Treasures”, by Barbara Perry Lawton, in the Summer 2009 edition of the Brooklyn Botanic Garden’s “Plants & Gardens News.”
Echinacea pallida, Pale Coneflower

The Shady Path

In this short section of the shady path on the north side of the house, I have my two big-leaved monsters: Rodgersia pinnata, on the right, and Kirengeshoma palmata, on the left. The Rodgersia has a lot of drought damage from our heat wave a few weeks ago, but it’s off-frame of this photo. I’m keeping a close watch on the Kirengeshoma, as it also crisps up at the slightest hint of drought. There are buds on it now, which mature very slowly into waxy yellow bells. It benefits here from its location next to my neighbor’s mixed border, which gets watered by soaker hose.

Part of the Shady Path

Both of these plants are several years old, possibly even a decade. I’ve lost track of when I purchased them. They’re slow-growing, but continue to increase in size every year, despite never being divided in all that time. They are well worth the wait.

I used to keep the Kirengeshoma in a large container, which I could never water enough. It’s much happier in the ground. Both of these plants would prefer constant moisture. I have long-term plans to build a rain garden in the shady part of the front yard. When the time comes, both of these plants will be very happy there.

Nestled between them in the foreground is a small, yellow-leaved, purple-flowering Hosta. I’ve lost the id for this. I think it might be ‘Little Aurora.’ Any Hosta aficionados out there who can weigh in on what this might be?

Hosta 'Little Aurora'?

Hosta 'Little Aurora'?

Heirloom Canna

Last to share with you today is the Heirloom Canna ‘Mme. Paul Caseneuve’ blooming in a large, glazed container in the front yard. This is the same specimen that I grew for the first time last year. I overwintered it in the same container in an unheated, but enclosed, section of the front porch. I’m surprised it came back.

Heirloom Canna 'Mme. Paul Caseneuve'

It doesn’t look as pink as I remember it from last year. The color is more apricot/salmony this year. At least it’s got the same bronze foliage.

Heirloom Canna 'Mme. Paul Caseneuve'

Related Content

Heirloom Canna “Mme. Paul Caseneuve”, August 17, 2007
The Shady Path (Flickr photo set)