A couple of weeks ago, Carol Michel, my podcast cohost, told me about a lecture from the Horticultural Research Institute in their tHRIve – WEB SERIES presented by Dr. Daniel Potter, a recently retired urban landscape entomologist from the University of Kentucky.
Sadly, the video is no longer available, but we think the information is important enough to share on the Gardenangelists’ podcast, and in our podcast newsletter.
Now, I’m writing a post about it.
Why? Because some of their research should change how we plant milkweed and which ones we choose to grow.
Here’s a quick recap of what we learned.
Plant more milkweed.
We need 2 billion more stems of milkweed. Urban and suburban gardens are more important than ever as there are fewer places where native milkweed grows in the wild. Everyone needs to plant milkweed in their landscapes and gardens.
Gardeners are the monarch butterflies’ last best hope. I’m not being dramatic here either. They are in serious decline, and we can help them.
Plant milkweed on the edge of the flower bed.
This was a huge surprise to me. I’d always been taught butterflies like messy gardens, but according to their research, Potter and his grad student discovered monarch butterflies visited milkweed plants more when they were planted at the outer edge of a garden bed, with the plants set off by mulch. Monarchs are visual searchers, and mulch helps them see the milkweed plants.
Plant milkweed with a North/South exposure.
Planting areas should have clear views of the milkweed from the north and the south, so monarchs see them as they migrate north in the spring and back south in the fall.
Plant tall milkweed.
Tall milkweed species received more visitors and caterpillars than shorter ones. In their studies, Asclepias incarnata (swamp milkweed), A. syriaca (common milkweed), and A. speciosa (showy milkweed) plants engaged four times as many monarchs as shorter milkweeds.
Note the researchers are from Kentucky. Oklahoma has several tall varieties of native milkweed you can plant in addition to the ones above, like A. viridis, green antelope horn milkweed. I see it in pastures, especially in spring. I planted it in my garden last year. Now, I need to move it to the front of the beds.
Avoid planting tropical milkweed.
In the recent past, I told you tropical milkweed is fine in Oklahoma because it dies completely, but new information from various sources, including the Xerces Society, shows it’s becoming a problem. I grew some this year, but I won’t in the future.
The good news? There is now more of a market for native milkweed now, along with showier cultivars of natives, sometimes called “nativars.”
Tropical milkweed can be bad for many reasons, including flowering longer, which may encourge monarchs to hang around too long missing their chance to overwinter in Mexico.
Monarchs can also become more susceptible to Ophryocystis elektroscirrha, called OE, because very few people, including me, can pronounce it.
Leave monarchs outside.
Unless you’re just trying to show the insects’ lifecycle to students, or you are an educator in some other fashion, experts are asking us to leave monarchs outside. Don’t try to raise monarchs indoors to release later, especially further south. The last generation of monarchs is called the Super Generation or Generation 5, which is larger and stronger than previous generations. Oklahoma and Texas are where that Super Generation is raised. It must be strong as monarchs migrate to their winter home in Mexico, and often indoor-raised monarchs aren’t strong enough.
Indoor raising may also mess up the monarchs’ directional cues from the circadian rhythm.
If you still want to raise monarch caterpillars, here’s how to do it outside.
Don’t just plant milkweed.
Butterflies and other pollinators need nectar plants too. I wrote a post about ten plants to attract hummingbirds, and honestly, many of these plants are also nectar and larval sources for other pollinators too. Attracting butterflies to your backyard isn’t hard. It just takes some planning. Email me about garden coaching if you read this information and feel overwhelmed. I help gardeners plan butterfly gardens all the time. It’s one of my favorite things to do.
Find native plants
Don’t know how to find out which native plants are best for your region? Check out this cool new interactive website from National Wildlife Federation called Garden for Wildlife with a link to Oklahoma’s native plants.
You can also grow many native plants from seed. I’ve used the Okies for Monarchs Central Oklahoma wildflower seed mix from the local Johnston Seed Company in my meadow for the past two years.
You can also buy native plants at various local plant sales. I’ve found native milkweed through High Country Gardens, including the named selection of A. incarnata (swamp milkweed) ‘Soulmate.’ Wherever you buy, ensure the plants are not treated with pesticides, including Bt.
Skip the cute butterfly houses and kill European paper wasps.
Don’t install those little butterfly houses with slits in them. In their studies, Dr. Potter and his graduate students found not only do butterflies not use them as shelter, but they are a haven for European paper wasps, an introduced predator of monarch caterpillars and many other caterpillars. European paper wasps are a voracious urban species and out-compete our native wasps for food. I have never seen one in my rural garden, thank goodness.
In addition to planting milkweed and nectar plants, you might consider making your garden a Monarch Waystation through Monarch Watch. At Journey North, you can also report monarch sightings, including eggs, caterpillars, and adults. Your citizen scientist reporting is a tremendous source of monarch information.
I hope this post was helpful. Some of the information was certainly new to me. Again, email me at dee@deenash.com for a garden coaching session if it’s too much info. I’d love to help.
Robin Ruff Leja
I always like to read the latest monarch news. I just never get enough of these beauties!
Dee Nash
It’s amazing to me how much new info is now out there. Give the scientists a few grants and see what they can do. 🙂
Perla S. Curbelo Santiago
What a wonderful briefing from Dr. Potter´s research, Dee! So many tips that I can incorporate in my garden in Puerto Rico. I do grow tropical milkweed here. Now I have to look for other strategies to make sure Monarchs move on and don´t hang out too much in my tropical paradise.
Dee Nash
Hi Perla, nice to hear from you! I wonder if you have some monarch butterflies that stay in Puerto Rico all year? I know California’s monarchs and Florida’s monarchs hang around all the time. I would be interested in reading more about how tropical milkweed is used in a tropical climate too. I know that in the states, people in southern Texas, Florida, Louisiana and California cut theirs way back in fall to stop the spread of OE. 🙂
Jane Schoedel
I have been raising monarchs for 3 years. This year was a struggle to find eggs. I have many common milkweed in my yard. The DNR in Wisconsin is requesting seeds. Many road sides are cut down by local & state highways. Can highway workers be told not to cut at the crucial months when eggs & caterpillars are in abundance?
Dee Nash
Hi Jane, thanks for stopping by. I know that several states are working with highway departments to stop mowing during migration periods. In Oklahoma, there is actually a multi-agency coalition working together to plant more milkweed and not mow during peak times. That’s as much as I know. On your common milkweed, it’s good to cut it back in July or August (before migration) so that it will grow new, softer leaves. I learned that in another talk I watched a few days ago.
Tammy Kupperschmidt
Wow! Thank you for all this info! I wanted to put in milkweed, but we were just building and moving in my disabled mother-in-law, and it all got to be overwhelming, so I only did Zinnias, roses, periwinkle and hydrangea. But next Spring, there will be milkweed!! I’ve been trying to learn about the different varieties and had heard as you said, avoid the tropical. I am also waiting until after Oct 6 to put BT on the Kale, but we had a HORRIFYING infestation of Cabbage Worm caterpillars who made our monster Kale dwindle to lace-looking desperate leaves with more holes than green kale!! We also had a snail infestation around 2 trees that I believe killed one of our Autumn Blaze Maple trees. That made me sad, but the hummingbirds still love the other Autumn Blaze and duck in and out of it between trips to the 3 hummingbird feeders! They also borrow the neighbors’ Crepe myrtles on their many trips and rest in the Crepe Myrtles between trips.
Dee Nash
Hi Tammy! Great! I think it’s ok to put Bt on your kale but just avoid overspray. The only caterpillar I know of that’s attracted to kale is the cabbage butterfly. They are quite common around my yard. I wonder which caterpillars went after your Autumn Blaze trees? I’m going guess tent caterpillars. If you use Bt on them, again, don’t spray on a windy day, and you’ll need to pierce the web or tent to make the spray get to them. You can also, if your trees are young, grab the caterpillars and pull them out of tree. I have to stomp on several every year on my Royal Raindrops crabapple trees. As for your plants, those are all great nectar plants. Great job!~~Dee