Our first Milkweed Guide posted back in the fall of 2010 and has continued to be one of our most-read blogposts. With spring here and butterfly gardeners chomping at the bit to create host and nectar habitat for Monarchs and other butterflies, it’s a good time to talk milkweed choices and availability.
Much has changed since that 2010 post. A three-year, drought-induced emphasis on native, drought-hearty plants has created a greater demand for native milkweeds. That said, supply continues to be lacking.
Monarch Watch recently launched its Milkweed Market on its homepage, a virtual marketplace of native milkweed seed. When you click on the vendors, though, most species are not available.
Monarch Watch, The Xerces Society, a pollinator advocacy organization, and the Native Plant Society have all engaged in milkweed restoration initiatives. This is good news, but it will take time to develop the market commercially.
Those of us who have attempted cultivation of native milkweeds from seed in our home gardens have often met frustration and failure. The very traits that make native plants so hardy also often make them extremely particular about their soil, drainage, moisture and available light. As George Cates, chief seed wrangler at Native American Seed Co. in Junction, Texas told me: “These milkweeds have a mind of their own.”
Monarch caterpillars will ONLY eat Asclepias species, or milkweed. Photo by Monika Maeckle
Plugs for native milkweeds are practically impossible to find in nurseries and because of their extremely long tap roots, transplanting them successfully often fails. Texas longterm drought has sparked a broader interest in native plants, so the availability of milkweeds and other “from here” pollinator plants will continue to grow.
For now, though, planting from seed is the most viable option. If you can collect your own seed in the wild, go for it. Native milkweed seed is expensive–as it should be. When you realize what it takes to produce the seed, you won’t begrudge its price tag. Read that saga here.
Since the time to take cuttings and collect seed will soon be upon us, we offer guidance below, based on personal experience. Other appropriate milkweeds are suggested in this article by the Native Plant Society. Keep an eye out for your local botanical garden or native seed society’s pop-up plant sales to score some proven homegrown natives.
Texas Butterfly Ranch Suggested Milkweed Species for our Area
Antelope Horn, Asclepias asperula
The most common native milkweed in these parts has fuzzy leaves and an odd greenish-white bloom and can stand two-feet tall. During dry spring seasons, the hearty perennial is sometimes the ONLY plant blooming. Last year in Central Texas when we had an exceptionally wet winter, the Antelope Horns were not as pervasive as you would think. Too much moisture and too much competition from less hardy plants kept these guys laying low.
Asclepias asperula, Antelope Horns Milkweed on Texas Hill Country roadside in April 2011, photo by Monika Maeckle
Antelope horns is especially appropriate for wildscapes, ranches, and large plantings. It can best be propagated by seed, which is available commercially from native seed suppliers.
Be mindful that stratification is recommended for successful germination. According to the Ladybird Johnson Wildflower Center, Antelope horns can also be propagated from root cuttings taken in the spring. If you have it growing in nearby fields, ranches or wildscapes, you might give this a try. If you choose to plant seeds you’ve gathered yourself, collect those in June.
Typically 30 – 45 days of stratification will be required before installing in moist soil. See our post on how to get Antelope Horns milkweed to germinate, courtesy of Native American Seed Company in Junction, Texas.
Green Milkweed, Asclepias viridis
This common native milkweed in our area is sometimes called Green Antelope Horn Milkweed or Green Mlikweed and is the most common milkweed in the state of Texas. The Edwards Plateau is the western reach of its range, which starts in East Texas.
Asclepia Viridis, Green Milkweed or Green Antelopehorn Milkweed Photo courtesy Ladybird Johnson Wildflower Center
I have a single one of these plants growing under a porch at the ranch. The solitary bloomer never receives supplementary water and barely enjoys rain, given its location tucked under a breezeway.
Yet every year it pushes out a batch of blooms and seedpods, peeking from under the deck, reaching for the sun. Those of us who raise Monarch caterpillars like the fact that Green milkweed has larger leaves than other available milkweed, which makes feeding voracious caterpillars a bit easier.
Green milkweed can range from one-three feet in height and is best propagated by seed which is commercially available. Like Antelope Horns, it sports showy whiteish-green globes of flowers that attract Monarchs as a host, and huge bees and other butterflies for its nectar.
Swamp Milkweed, Asclepias incarnata
Another excellent native milkweed for our area is Swamp Milkweed, a lovely pink bloomer that sports lush pink flowers in August and blooms through September.
Swamp milkweed grows along rivers and streams and is an excellent choice for riverbanks in the Hill Country or perhaps in an area where you have air conditioning condensate draining. Spiders LOVE this plant. I have witnessed “death in the afternoon” more often than I care to remember: Monarch butterflies snagged by orb weaver spiders as they perch on Swamp Milkweed leaves, in search of an easy feast.
Monarch on Swamp Milkweed on the Llano River, photo by Monika Maeckle
For years we’ve had this milkweed growing along the banks and on the Chigger Islands of our Llano River ranch, but recent, prolonged drought has taken a severe toll, lowering our water table so much that much Swamp milkweed has died.
Butterfly Weed, Asclepias tuberosa
This bushy orange bloomer is often confused for Tropical Milkweed (see below) and is frequently mislabeled at nurseries. One of the best ways to tell if a milkweed in question is tuberosa is to break off a leaf and see if milky latex pours out. If it doesn’t, then it’s Butterfly Weed.
Asclepias tuberosa, or Butterfly Weed, is a great nectar plant for Monarchs and other butterflies. Photo courtesy Ladybird Johnson Wildflower Center
Detractors of Butterfly Weed point out that it doesn’t contain the toxic cardenolides that protect Monarchs from predators, thus should be avoided. The toxins, contained in the latex of most milkweed species, give the Monarch its bright warning colors and bad taste that deters predators.
The 18-inch-tall perennial serves as a fantastic nectar plant. Its abundant orange blooms attract all kinds of butterflies. If you’re trying to stick with natives, choose this one to grace your butterfly garden.
Butterfly weed can sometimes be found locally at nurseries. The plant is propagated easily from seeds and cuttings and blooms through the Fall, when nectar sources are wanting.
Tropical Milkweed, Asclepias curassavica
Tropical milkweed is not native, but it is widely available at garden centers in one-gallon pots and it also germinates easily from seed and cuttings. As much as I support native plants, this is my favorite Monarch host plant. It’s easy to grow, not a water hog, propagates easily from seeds and cuttings, blooms prolifically and draws Monarchs like a magnet. Commercial butterfly breeders and even organizations like Monarch Watch rely on Tropical milkweed to raise butterflies in captivity.
Asclepias curassavica, Tropical milkweed, NOT native, but a great Monarch host and nectar plant for all butterflies. Photo by Monika Maeckle
The plant can be controversial for native plant purists and some scientists. Theories abound on the appropriateness–or not–of Tropical milkweed in Central and South Texas.
The plant originated in Central America and has gradually moved north. Dr. Chip Taylor, founder of Monarch Watch, points out that Tropical milkweed is the plant on which Monarch butterflies evolved.
In my completely unscientific kitchen experiments, I’ve noticed that Monarch caterpillars PREFER Tropical milkweed. When offered a choice of Tropical milkweed, Swamp Milkweed or Antelope horns, Monarch caterpillars inevitably choose Tropical milkweed.
Studies show that the toxins in Tropical Milkweed inoculate Monarch moms and their young. While it can be challenging to find Tropical milkweed in the Fall when Monarchs are moving through Texas, it’s easy to cut back your spring plants to encourage new growth for migrating visitors. My butterfly breeder friend Connie Hodson, of Flutterby Gardens in Manatee, Florida, says you can cut any six-inch stalk of Tropical milkweed in a potting soil and vermiculite mix, and have new plants in no time. You can also order seeds or harvest them yourself from fellow gardeners.
NOTE: If you choose to plant Tropical milkweed, best practice suggests slashing it to the ground in late fall or early winter. It will push out new shoots as the weather warms. This will discourage overwintering of organisms possibly harmful to Monarchs.
Matelea reticulata Pearl Milkweed vine
Milkweed vine, lovely addition to the garden! Photo by Monika Maeckle
While Milkweed vine is in the Asclepias family, there doesn’t seem to be any evidence that Monarchs and Queens use this vine as a host plant. It grows in the wild in the Texas Hill Country.
Anyone have experience with Milkweed vine as a host?
I include it today because it is an absolutely delightful plant with its heart-shaped leaves, perfect green symmetrical flowers, and a lovely, intriguing pearl-like dot in the middle. Someone needs to make earrings out of these flowers.
In the Fall, Milkweed vine produces huge seed pods, about three times the size of Tropical milkweed. The plant climbs and curls for six – 12 feet and is sometimes called Green milkweed vine, Net vein milkvine, and Netted milkvine.
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