What do Monarch butterflies need?
Series
This is bonus content for #06 of How to Save the World With Plants: “Secret milkweeds”
You’ve just seen Monarch fall migration. Now’s the time to get ready for next year’s Monarchs!
The cooling fall period, when perennials can put down roots and then grow slowly through the winter rains, is a great time to plant. You can also plant in winter when they are completely dormant and being planted doesn’t stress them. This may feel weird if you have gardened further north, but the soil rarely freezes solid for more than a few days here, and not even that deep. I consider winter planting to be after first frost through around February or March. Once it starts getting warmer in March through May, planting requires more and more water to sustain establishment through the first year. (Even drought tolerant plants often need babied the first year if spring or summer planted.)
Host plants
Milkweeds are the host plants for Monarch butterflies. They also host a lot of milkweed specialist insects, such as milkweed beetles, milkweed bugs (multiple kinds!), and various specialist moths. Here are some commonly available local-ish milkweeds in order of ability to tolerate dry conditions
Driest
- Asclepias asperula
- Wants their soil dry!!
- Apparently hard to start, as only a few nurseries carry it
- Asclepias viridis
- One of the most abundant local species
- Get some if you have sun and don’t live in a swamp!
- Cynanchum laeve (vine)
- Probably the most abundant local species, as it’s a common “weed” in yards
- If you have it and don’t like where it is, you can dig it and move it to a trellis. Once it climbs, it flowers!
- Differentiate it from the invasive morning glory “bindweed” by rounded parts on the leaf closest to the stem. Bindweed has a more arrow-head shaped notch near the stem.
- Asclepias verticillata
- Spreads by underground roots
- Skinny leaves, somehow still delicious to Monarchs
- Asclepias tuberosa
- Often covered in aphids, just let them be
- Easiest to start from seed in my experience
- Asclepias amplexicaulis
- Sand specialist
- Asclepias viridiflora
- I have a really hard time getting this one started but it’s consistently around in nature in less-disturbed prairies
- Matalea biflora (vine)
- Sneaky low grower, weird cool red flowers in pairs
Medium-dry to medium-wet
- Matalea decipens (vine)
- Not common in the wild here, tends to be more east
- Asclepias syriaca
- Does best in part shade, or with some supplemental water if full sun here in Norman
- Not common in the wild here, tends to be east and north (?) states
- Gonobolus suberosus (vine)
- Damp-ish, can take part shade
Medium to wet
- Asclepias speciosa
- Mine dies back if it doesn’t receive regular water
- Asclepias sullivanti
- Not common in the wild here, tends to be northern plains
- Asclepias incarnata
- Common name is “swamp milkweed”. Keep it wet.
What about non-native milkweeds?
I do not advise planting these even though Monarch caterpillars will enthusiastically eat them. Links below on why.
- Asclepias curassavica (Tropical Milkweed)
- Gomphocarpus physocarpus Hairy Balls Milkweed or Balloon Plant
- Similar potential for confusing the seasonal cues that Monarchs use to determine when to go south
Nectar plants
Fall migration staples for nectar include
- Liatris mucronata (Blazing Star)
- The latest fall bloomer, thrives in the driest years once established)
- Verbesina virginica (Frostweed)
- Verbesina enceloides (Cowpen Daisy)
- Helianthus maximiliani (Maximilian Sunflower)
- Salvia azurea (Pitcher Blue Sage)
- Salvia greggii (Autumn Sage)
- Any Solidago species (goldenrod)
- They all bloom in the fall
- They are insect pollinated, not wind-pollinated, so they are commonly blamed for ragweed allergies
- Malvaviscus arboreus var drummondii (Texas Mallow or Turk’s Cap)
Spring migration is slower, but plants blooming at that time can include
- Asclepias viridis
- Asclepias asperula
- Asclepias tuberosa
- Salvia greggii (shrub)
- Conoclinum greggii
- Glandularia bipinnifitada
- Lantana horrida
- Salvia farinacea
- Coreopsis lanceolata
- Prunus mexicanus (tree)
- Prunus angustifolia (shrub)
- Malvaviscus arboreus var drummondii
You can browse iNaturalist to see an array of ideas, but generally if it blooms from March to June in our area it’s probably going to help the spring migration.
Safety from harm
Do not use any insecticides in your garden! Let aphids eat the milkweed! If you really want them gone, squish or wash the aphids off by hand. Any thing that’s going to harm the aphids will also harm your Monarch caterpillars and other milkweed specialist bugs.
Sleeping places
They generally roost in both deciduous trees and evergreen trees on their journey. I would advise not treating any of your trees with pesticides. If you have the opportunity to plant a new tree, picking a native species is generally better for pollinators in general.
How to get your plants!
Germinating milkweeds can be a bit tricky. Lady Bird Johnson Wildflower Center has a germination guide. I find A. tuberosa has the most consistent germination of the dryer-habitat milkweeds.
Some local and semi-local sources for milkweed plants where I have purchased
- Sanctuary Gardens
- Lia’s Garden
- Blue House Urban Farm, usually at spring and fall plant festivals
- Wild Roots Oklahoma, usually at spring and fall plant festivals
- Native Plant Nursery OKC
- Prairie Wind Nursery
- Missouri Wildflower Nursery (online)
Online seed sources include
- Native American Seed
- Johnston Seeds Okies for Monarchs Central Western Mix
- Missouri Wildflower Nursery (online)
Feel free to email me if you are trying to find a particular one and need help judging an online source. (I’ve noticed several sketchy looking websites I hadn’t seen before, that have some tell-tale signs in the “about us” pages of non-reputable sources.)