Monarchs prefer this inconvenient vine in my yard

By Peggy Whetzel

Growing wild in my yard is a native vine that’s never offered for sale, Cynanchum laeve, commonly called honeyvine, probably for the elongated, heart-shaped leaves. It’s also called vining milkweed or sand vine.  By now, if you have it in your yard, chances are this weedy-looking perennial is climbing over your favorite flowers. Of course, your impulse is to yank it out.

But please, do it carefully. Monarch eggs or caterpillars may be attached.

Closeup view of a striped monarch caterpillar chewing the stem of a honey vine plant growing in St. Charles, MOt

This monarch caterpillar was thriving on honey vine growing in a perennial bed at Parkview Gardens in St. Charles, MO just a few blocks from my house.

In my yard, honeyvine has proven itself to be the host plant preferred by monarch butterflies over any of the milkweeds (Asclepiadaceae) I cultivate, including swamp milkweed, butterfly weed, tropical milkweed, and common milkweed.

In April or early May this year, I spotted a honeyvine sprouting annoyingly in my brick driveway.  I yanked it. Then I remembered to check for an egg, and sure enough, there was one.  So I put the vine in a glass of water in the windowsill.  After a few days, I spotted a tiny striped caterpillar nibbling away.  About two weeks later, I released the beautiful butterfly it had become.

If I kept every honeyvine that sprouts, my garden would disappear.

But do keep a few growing somewhere in your yard through the month of October.  And when you remove or trim vines growing in inconvenient places, do so gently, checking for chrysalises, caterpillars and eggs.  Luckily, the whitish-to-yellow monarch eggs tend to be laid, one per leaf, on the backs of leaves or stems near the vine’s tender tip.  To spot young caterpillars, check leaves and stems that have been eaten.

Long, heart-shaped leaves, smooth stems and foliage, and milky sap distinguish honeyvine from other vines.

Honeyvine (Cynanchum laeve) has non-hairy foliage distinguished by elongated heart-shaped leaves. I’ve read that honeyvine does not have milky sap. But that’s likely an error, and milky sap from a cut stem helps identify it.

If you find any butterflies-to-be, put the cut vine in a jar of water, and set it in the shade in direct contact with a honeyvine that is still growing. Nature should do the rest.  Or, take it in and raise it. The Family Butterfly Book by Rick Mikula is very helpful.  If you find a chrysalis, always keep it or tie it up in the shade so the pupa will not dehydrate.

As a bonus for allowing honeyvine to grow in your yard, bees and other pollinators enjoy the vine’s clusters of milkweed-like, greenish-pink-white flowers.


10 thoughts on “Monarchs prefer this inconvenient vine in my yard

  1. I think this is the vine that has been trying to take over one of the flower beds in my front yard. I don’t want it to overgrow the spicebush I planted this spring, but I want to support monarchs. Tough choice!

  2. Thanks, Peggy. Your blog supports information I recently heard from a friend. I understand honeyvine vine looks a lot like the common bind weed – which is not welcome in my garden – but that vining milkweed has more of a heart-shaped leaf with white veins. I’m assuming the best way to get this plant is from seeds. I’m impressed that it is attracts monarchs. Perhaps I’ll look for some seeds.

  3. Great information. Apparently it is the white veins that distinguish it from field bindweed.

    It does indeed make more than a pest of itself in the garden, but I will know be more careful when removing it.

  4. I have also seen monarch caterpillars on this vine in my yard.
    I have told people this before and I think they doubted me.
    Thanks for the photografic proof.
    Kathy Bildner

  5. Very helpful. Could you perhaps put together a post to help us identify honeyvine, bindweed, and buckwheat? I can only really tell by looking at the flowers.

  6. Thank you for all these comments!

    It turns out that looking for milky sap is not proof that this is honey vine, because I have seen it both ways. Hmm. I’ll look into that some more.

    Regarding identification, if you compare the florets (if that is the right word) on common milkweed, swamp milkweed and tropical milkweed, you’ll see that the structure is similar. I will check into the bindweed similarity.

    It is a fast-growing plant, but not a heavy vine, thank goodness. If you haven’t seen any monarchs in your neighborhood, chances are good that if you just look the vine over for caterpillars and check the tips for eggs it’s OK to cut it away from your favorite flowers.

    I have seen very few butterflies since April and May.

    Again, thanks everybody!

  7. Peggy, what about growing these in pots at the base of a trellis? Do you think potting them and cutting off seed pods could effectively contain them? Thanks in advance, Tony

    • Tony, I think that is a great idea. And you can save the seed pods for giving away or distributing, with permission. In my opinion, everyone should have one, and, as you say, collect the pods at the end of the season.

      By the way, this vine dies to the ground each winter, which is why I thought it was an annual. If it appears in the lawn it is easily mowed, and that is that. It only really gets going in mid-to-late summer, so if you dig or pluck unwanted vines out early on, they won’t climb your favorite plants.

      But for me, if I find a caterpillar to raise, I’m really grateful for whatever vines I can harvest from the yard. I’m also grateful that they do well in nothing more than a glass of water.

  8. Brian,
    You have my sympathies, but it’s an easy vine to dislodge – at least I think so. Weed it out and dig it up if it’s growing where you don’t want it. Chances are the vine is growing somewhere else in your yard that you might not mind so much. It’s possible to transplant it.

    I like Tom Terrific’s advice to grow Asclepias curassavica, aka blood flower or annual milkweed, for monarchs. It’s not native to our area, but it is well-behaved and it’s native to South America, which is close enough for me. And monarchs are in trouble, we need to help them.

    Back to the vine – as you weed (and you might want to dig it out with a trowel), check the end of the vine for single eggs laid on the back of a leaf from April through October. Lacewings also lay eggs on this vine – the eggs look like they are on stems. If you spot an egg(s), put the vine with the egg leaf in a glass of water and give it to someone to raise (I volunteer). Or put it in a sheltered shady spot- preferably next to another milkweed plant – and keep water in the glass until you see the caterpillar eating the leaf in a few days. If the original host vine is touching the other milkweed plant, the little guy will eventually crawl onto that and keep growing.

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