Monarch butterflies previously considered Threatened, have now been classified as Endangered by the International Union for Conservation of Nature, the world’s most comprehensive scientific authority on the status of species. Two major driving factors are habitat loss (and thus, food loss), and climate change.
“The numbers of Western monarchs, which live west of the Rocky Mountains, plummeted by an estimated 99.9 percent between the 1980s and 2021. While they rebounded somewhat this year, they remain in great peril. Eastern monarchs, who make up most of the population in North America, dropped by 84 percent from 1996 to 2014. The new designation of endangered covers both populations.” (New York Times.)
Monarch butterflies overwinter in a few hectares of forest in central Mexico then migrate as far north as Canada and back again, a 2,500-mile journey. Along the way, they deposit their eggs on Milkweed plants, especially Asclepias tuberosa, A. speciosa, A. incarnata, A. viridis, A. syriaca, and others (there are more than 100 species of milkweed in N. America, and monarchs are known to use about 27 of them). Milkweeds are the only plants that Monarch caterpillars can eat, and they contain toxic cardiac glycosides (cardenolides), that protect both the larval and adult Monarchs from predators.
In 1986 the Mexican government created a reserve to protect the overwintering habitat, helping to stem the loss of this important habitat. However, in the U.S., farmers use of GMO Crops that were able to withstand glyphosate, a key herbicide in Roundup, had a devastating impact on milkweed plants, destroying about 99% of milkweed growing in the fields. Monarchs are also being killed by garden pesticides and mosquito sprays like Permethrin, which contaminate milkweed, kill larvae feeding on those plants, and kill adult butterflies that contact it. Neonicotinoid insecticides have been shown to harm and kill Monarch eggs and larvae. In addition, worsening climate change is expediting a mismatch between when insects migrate through an area and when the forage plants that they depend upon are in bloom.
“Monarch experts are eager to enlist the public’s help in saving the species. Their message: Plant milkweed that’s native to your region, which probably means avoiding tropical milkweed (it can do more harm than good, especially in the South). Swamp milkweed is an attractive, easy-to-grow variety native to all but the most western areas of the contiguous U.S, including Colorado. It is one also of the few milkweed species that do not spread by underground rhizomes. That’s for the egg-laying and caterpillars. The butterflies need nectar, so plant native flowers that bloom when monarchs are in your area.” (NYT)
One plant in particular stands out as a true magnet for foraging monarch butterflies – Liatris ligulistylis, and its native range extends into the Colorado Eastern-slope front range. This late-summer blooming tower of flowers emits a pheromone also exuded by Monarch butterflies, so they are inexorably drawn to it in numbers. It’s a treat to watch! There are many other nectar-source flowers they will visit, and Harlequin’s has excellent lists to guide you.
Harlequin’s Gardens grows and sells hundreds of milkweed plants every year. Currently, our stock is low, but we’ll be well stocked next season. It is important to note that Asclepias curassavica (Tropical milkweed) is not an adequate substitute, and in fact can be detrimental to monarch butterflies.
WHAT MONARCHS NEED, AND HOW YOU CAN HELP
According to the Common Sense Pest Control Quarterly, published by the Bio-Integral Resource Center:
To survive, Monarchs need water, milkweed, nectar sources, and trees on which to overwinter. Milkweed provides food for caterpillars and nectar sources for adults. Adults can also utilize many of the nectar plants that sustain bees, biological controls, and other butterflies. Trees needed must be in critical climate zones that provide moisture and shelter from storms and other disturbances.
Monarch restoration is the goal of many environmental groups. Bringing Back the Monarchs is a project of Monarch Watch, which encourages home gardeners to plant milkweed and nectar plants, and in return will register the garden as a Monarch Waystation. Recommendations include an area of at least 100 square feet, six hours of sun per day, low-clay soils with good drainage, at least 10 milkweed plants, preferably from several species, and at least four species of nectar plants. Other organizations with pollinator and butterfly garden certification include the Xerces Society, Monarch Joint Venture, the North American Butterfly Association, and Wild Ones.
These drought-tolerant plants play a critical role in supporting a tremendous range of pollinators and occur in nearly all eco-regions. The showy flowers of milkweeds offer abundant, high-quality nectar to pollinators, making them notable honeybee plants in many parts of the country. However, an enormous range of other pollinators, from hummingbirds to butterflies are also frequent Milkweed visitors.
Milkweeds are named for their milky latex sap, which contains the chemicals that make the plants un-palatable to most animals. Not surprisingly, Milkweeds are normally highly deer-resistant, and livestock also tend to leave them alone because of the bad taste. The plants have interesting fleshy, pod-like fruits that split when mature, releasing the seeds. Fluffy hairs, known as pappus, silk, or floss, are attached to the seeds. These aid in wind dispersal.
Milkweed flowers have a unique structure and are pollinated in a more specific way than most insect-visited flowers. Rather than occurring as free grains that are accessible to any visitor, milkweed pollen is contained in pollinia, waxy sacs located inside vertical grooves of the flower. When an insect visits the flower to obtain nectar, one of its legs may slip into a groove (“stigmatic slit”), attaching pollinia to the insect’s leg. Fertilization occurs when pollinia are then inadvertently transferred by the insect to another milkweed flower.
Milkweeds have a variety of ethnobotanical uses. Native Americans used stem fibers to make string, rope, and cloth. Also, the sap was used by some tribes to heal sores and cuts and for removing warts. The cardiac glycosides present in the sap of the milkweed are allied to digitalins used in treating some heart disease. Native Americans made a tea from milkweeds as a tonic to strengthen the heart and the Navajo also used it as a treatment for the bite from a rabid animal.
During World War II, Milkweed’s silky floss was used to fill life vests and aviation life jackets and is currently used as hypo-allergenic filling for pillows and comforters. Milkweed silk is 5 to 6 times more buoyant than cork.
ENHANCING BEE SURVIVAL
Extensive research demonstrates that crops with sufficient nearby natural habitat can achieve all their pollination from wild native bees alone, and that managed honeybees are healthier and more resistant to diseases when they have access to diverse and abundant floral resources. As high-quality nectar producers, milkweeds play an important role in supporting bees.
ATTRACTING BENEFICIAL INSECTS
In addition to attracting pollinators, Milkweed nectar supports beneficial insects that are natural predators of many crop pests. A recent study evaluated 43 species of native flowering perennials for their potential to attract beneficial insects. Showy Milkweed (Asclepias speciosa) attracted the highest number of beneficial insects of any plant species.
GARDENING WITH MILKWEED
Milkweeds are adaptable and easy to grow. They need sun (fewer flowers produced in shade) and can be quite drought tolerant. When planting, mulch heavily, or better yet, plant next to a boulder. Water well the first month, then ignore.
It is very important to make sure your garden is not toxic. Using chemical pesticides on your garden plants or in your soil, especially those containing neonicotinoids, runs completely counter to supporting pollinators and the plants that attract and feed them. And using Round-Up or any other glyphosate herbicides will kill milkweed. The Natural Resources Defense Council has filed suit against the EPA’s approval of Dow Chemical’s new herbicide ‘Enlist Duo’, which pairs glyphosate with 2,4-D.
DOING OUR PART
We at Harlequin’s Gardens have always believed that the more we appreciate how everything relates, and the more we learn to serve the whole, the more we enjoy the process of gardening, and through that relationship, we grow. And so, while only a small area of SE Colorado is part of a large spring breeding area for Monarch butterflies, and Colorado is on the fringes of both their Eastern and Western migration routes, it is still important for us to participate in efforts to support and increase populations of these remarkable creatures.
To that end, Harlequin’s Gardens has increased both our selections of important Monarch-supporting plants and increased the quantities we carry. ALL of our plants are free of neonicotinoid pesticides. This year we are offering the following milkweed species:
Asclepias tuberosa (Orange Butterfly Weed)
Asclepias speciosa (Showy Milkweed)
Asclepias incarnata (Rose Milkweed or Swamp Milkweed)
Asclepias verticillata (Whorled Milkweed)
Asclepias asperula (Antelope Horns, Spider Milkweed)
Liatris ligulistylis (Meadow Blazing Star)
and dozens of wonderful nectar-source native species, including Liatris ligulistylis (Meadow blazing Star)!
HERE ARE THEIR PORTRAITS:
ASCLEPIAS TUBEROSA (Orange Butterfly Weed)
Certainly NOT a weed, this essential butterfly plant is irresistible to butterflies, hummingbirds, and people. The very long-lived, tap-rooted plant may be slow to establish and reach its mature size, but its showy umbrella-like clusters of small, vivid orange blossoms attract legions of butterflies (and hummingbirds). Best in full sun with low to moderate water. Requires good drainage or loamy soil. Care should be taken not to over-water, especially in young dormant stages. Tough and durable once established. Well worth the effort. Hardy to zone 4. Grows 20-30″ tall by 12-15″ wide.
ASCLEPIAS SPECIOSA (Showy Milkweed)
A bold and beautiful clumping and spreading rhizomatous native plant to 3-4′ tall, with attractive large, silvery-green, soft leaves and very fragrant 3-4″ dense round clusters of antique rose flowers of fascinating design in late spring/early summer. Found in habitats ranging from sunny and dry to moist in savannahs, prairies, roadsides, old fields, and meadows. It’s very tough and vigorous and you can grow it next to your driveway, in your dry “hell strip”, somewhere your hose won’t reach, on a hillside, and especially in a xeric or native garden. Grow it in full sun, in virtually any soil (it is very tolerant of alkalinity and poor, dry soil). Water it a bit the first year and don’t worry if it disappears; it’s just going temporarily dormant. Once established, the Monarch butterflies, who can smell a milkweed a mile off, will come to it for larval food and for nectar and lay its eggs on the undersides of the foliage. It is the native hostplant for our Western Monarch butterfly. The alkaloids associated with milkweeds give the monarch and other butterflies that feed on it protection from predators. Painted Ladies and other butterflies and moths also swarm to Showy Milkweed, as do honeybees and native bees. Conspicuous, showy large boat-shaped seed pods ripen from green to tan and split open to reveal glistening white, incredibly silky, soft seed parachutes. Showy Milkweed needs cross-pollination for fruit and seed development. Cold hardy to zone 2, or 8000 feet. (Photo Credit: Beth Waterbury.)
ASCLEPIAS INCARNATA (Rose Milkweed or Swamp Milkweed)
Commonly referred to as Rose or Swamp Milkweed because of its association with highly saturated soils in wetlands or areas that are flooded seasonally, our native Asclepias incarnata can also thrive with moderate moisture. The erect, 2 to 5’ tall clump-forming (not spreading) plants usually have a taproot of 18” or more, with the root crown producing one to six or more stems each growing season. Space the plants 2-3’ apart. The pink or white flowers, which give off a sweet vanilla scent, are presented in flat umbels, blooming over a long period in summer. Their nectar attracts many pollinators, including Monarch, Buckeye, Tiger Swallowtail, Fritillary, and Hairstreak butterflies, as well as honeybees, bumblebees, Hawk moths and hummingbirds! This refined milkweed is an excellent choice for rain gardens. The long-lasting blooms make a great cut flower, and the long, narrow brown seed pods are decorative, too. Grow in full sun, in fine to medium-textured soils, enriched with compost at time of planting. All species of Asclepias are late to emerge in the spring, so don’t be concerned if other perennials come up first and they remain dormant, and don’t forget it’s there. Hardy to Zone 3a, deer-resistant, and toxic. In the past, the roots of swamp milkweed were simmered to make a tea taken in small quantities both as a general purge and to destroy and expel parasitic worms.
ASCLEPIAS VERTICILLATA (Whorled Milkweed)
Of all milkweeds in the United States, Whorled Milkweed is one of the most broadly distributed. While not native in CO, it is found in all the states south, east and north of us. This widely adaptable and tough regional native is distinguished from other milkweeds by its smooth, needle-like, whorled leaves arranged on a generally unbranched stem to 2’ tall. Due to its long, narrow dark green leaves and stems, this species blends in with grasses and is easily overlooked when not in bloom. The sweetly scented white blooms appear between July and September in clusters near the top of each plant, later in the year than many other Milkweeds. The nectar of the flowers attracts many kinds of insects, including long-tongued bees, short-tongued bees, wasps, flies, butterflies, skippers and beetles. Because this species is one of the last milkweeds to senesce as the season progresses, it is a common late season host plant for Monarch butterfly larvae. In autumn the leaves turn yellow to orange, and the pencil thin seed capsules are very decorative when they split open to reveal the silky seeds. Whorled Milkweed is deer and rabbit resistant. Note that it is rhizomatous and will spread. Found in dry fields, roadsides, and shale barrens, it needs no coddling, is widely adaptable and tough, and best located where it will have room to spread in a sunny or lightly shaded dry spot, but it will tolerate average to moist garden soil as well. Hardy to Zone 3 or 4. Please note, Asclepias verticillata is highly toxic to livestock and horses and should not be allowed to take root in pastures or hay fields.
ASCLEPIAS ASPERULA (Antelope Horns, Spider Milkweed)
Antelope Horns is a very distinctive and attractive, clump-forming, 1-2’ perennial with an upright or sprawling habit. The green stems are tinged maroon and densely covered with minute hairs. Its airy open network of narrow leaves topped by very large spherical flower clusters of greenish-white flowers with maroon highlights make it easy to identify. It blooms from April through June. As the green seed follicles grow in length and begin to curve, they are said to resemble antelope horns, thus one of its vernacular names.
Native from KS to CA, ID to TX & Mexico, Antelope Horns is not finicky about water. It has a large tap root that develops quickly which allows it to flower even during years when rainfall is scarce. It prefers to grow in well drained soil in full sun and is commonly found in meadows, semi-desert, roadsides, washes, brush, and woodlands, favoring moist, sandy, or rocky soil, and will also grow in well-drained caliche, loam, or clay.
Antelope Horns serves as a larval host and nectar source for Monarch and Queen butterflies, and attracts other butterflies, honeybees, huge bumblebees and many other native bees as pollinators. Cold hardy to -20 degrees Fahrenheit.
LIATRIS LIGULISTYLIS (Meadow Blazing Star)
This outstanding Great Plains native is a butterfly magnet during its long summer bloom (July through September). We have seen swarms of Monarchs feeding on this Liatris in Lauren Springer Ogden and Scott Ogden’s Fort Collins Garden, where it grows 3-5′ tall. The numerous crimson flower buds open to large, bright purple-pink florets that bloom over an extended period in summer. It is a prairie native, the Front Range being the farthest western portion of its range. Give it full sun, or sun with late-afternoon shade in loam or clay soil and deep, infrequent waterings once established. And make sure it’s located where you can watch the show! After flowering, the seeds are a favorite food for goldfinches. Hardy to zone 4.