In gardening circles, we tend to throw around the word ‘weed’ haphazardly, using it to refer to plants that turn up where they weren’t intended. But what truly classifies a weed? What makes a plant that turns up unannounced undesirable? If you’re examining this year’s volunteer plants, determine if any milkweed species are valuable for butterflies before you toss them.
Among gardeners who cultivate pollinator gardens, that is, gardens that primarily serve the purpose of sustaining pollinators, the word ‘weed’ certainly has a different connotation. Possibly a different meaning altogether. It could be because we know that the plants that seem to come out of nowhere are typically a food source for pollinators.
When it comes to pollinator gardens, there is one ‘weed’ that is indispensable. Without this plant, we are likely to miss out on the most recognizable pollinators. Milkweed is the sole larval food for the beloved monarch butterfly. It is also a valuable nectar source for all types of pollinating insects and hummingbirds.
Sadly, the monarch butterfly population has dwindled drastically in recent years, with a 22% decrease in population over the last year alone. Deforestation and urban development have destroyed much of the monarch’s migration ground in Mexico and California, and pesticides and herbicides have marred habitats all around the United States.
Many factors are stacked against the monarch’s existence and contributors to its endangered classification. As gardeners, we are limited in what we can do about many of these things. But, what we can do is help maintain their host plants and give them sanctuary in our own garden spaces. Here are 21 types of milkweed native to different regions of the United States. Cultivate one or more in your garden to help sustain the monarch population and feed other native pollinators.
Antelope-Horns Milkweed
Antelope-horns milkweed is a clump-forming plant with lanceolate leaves and intricate star-shaped white and purple flowers.
This long-blooming milkweed species has an interesting name derived from the appearance of the seed pods, which resemble antelope horns. The plant is clump-forming, with long, thin, lanceolate leaves that fold lengthwise slightly and stems ranging from bright green to a slight purple cast.
Their round clusters of flowers are wonderfully intricate. Each small flower has five light green petals arranged in a star shape. The interior of the flowers is white and purple with five small hoods that spread in a star shape as well when the flowers bloom. The plant stems are lightly pubescent, but the leaves are not.
Aquatic Milkweed
This species attracts butterflies with its sweetly scented nectar.
Aquatic milkweed or white swamp milkweed is a small to medium-sized variety native to marshy areas of the southern U.S. It has umbels of lightly fragrant, white flowers. The blooming season is in late spring, and this species is important to monarchs returning from their winter migration.
Butterflies and bees are fond of these little flowers, as they are a great source of nectar. Aquatic milkweed is evergreen, making it very important to overwintering butterflies in Florida.
The blooms top off slender purple-to-green stems flanked by short, narrow leaves. The entire plant can have a pink cast in some cases. The seeds are different from most species. Rather than the fluffy seeds produced by most types of milkweed, aquatic milkweed seeds are winged and designed to float on water. This variety is very tolerant of damp soil environments.
Arizona Milkweed
This species features small white-pink clusters of flowers that attract butterflies.
Arizona milkweed is native and endemic exclusively to southern Arizona. This shrubby, small species grows in clumps, preferring dry, rocky soil and high elevations. It is commonly found growing on mountains and in woodland areas. The stems are tall and unbranched, with thin, lanceolate leaves that vary in density.
The flowers are small and white to pink, appearing in clusters atop the thin stems. The outer petals are slightly reflexed, with horns that extend beyond the hoods. It is an important species for monarch survival and serves as an important food source for carpenter bees.
Broadleaf Milkweed
Broadleaf milkweed has large leaves and creamy white flowers that are toxic to animals.
This very robust and sturdy species is a native plant from the Great Plains to the West Coast. It has a very different leaf configuration than most species. The leaves are quite broad and elliptical. They form a loose rosette around a main stem. These leaves can grow quite large toward the base of the stem.
The flower clusters are partially obscured by the leaves, which tend to grow in an upward-facing fashion. The flowers are creamy white to pale green, with petals and sepals reflecting away from the hoods.
This species is known to pop up where grazing animals can come in contact with it. Unfortunately, it is highly toxic to these animals and also to pets, as all milkweed species are.
Butterfly Milkweed
Butterfly milkweed is a compact native species with stiff stems and bright orange flowers.
Topping out at only two feet tall, butterfly milkweed is a smaller variety. The leaves are large, stiff, and lanceolate, flanking stiff stems that support umbels of bright orange flowers. This variety is native to most of the United States and Canada and blooms all summer, providing an important food source for butterflies.
This species does not produce the sticky, white sap that most milkweed species do. It likes full sun and well-drained soil and is virtually pest and disease-free. This species will also attract hummingbirds and bees and makes a nice cut flower with a long vase life.
California Milkweed
This drought-tolerant milkweed species plays a critical role in supporting pollinators in California.
California has its fair share of milkweed species that call the state their home. This species, which is endemic to a small region in the southern part of the state, also shares the state’s name.
California milkweed is a highly drought-tolerant plant, and the foliage is covered in soft hairs, which help to protect the plant from intense sun exposure. It typically pops up in sandy and clay-heavy soils on hillsides.
This species produces an abundance of flowers that are highly attractive to butterflies. The flower clusters are pendulous and downward facing, and when still in bud, they are also covered in soft, downy hairs. The sepals open and reflex away from pink, bulbous anthers. The leaves of this species are larger than most milkweed species.
Common Milkweed
This widespread plant is loved by butterflies, hummingbirds, and gardeners due to its attractive flowers and growth habit.
As its name suggests, common milkweed is highly available and widely cultivated throughout most of the country. It is beloved by butterflies and hummingbirds, and as a result, gardeners as well! It has an upright growth habit with large, ovate leaves and spreads by underground rhizomes.
The flower umbels are nearly spherical, forming pretty pink balls atop the branching, green stems of the plant. The flowers are quite small and wonderfully fragrant, with reflexed petals. This species is excellent at colonizing and spreads freely by windborne seeds.
Desert Milkweed
This species thrives in dry, hot conditions with poor soil.
Desert milkweed needs dry, hot weather and sandy soil conditions to flourish. It sounds strange, but it’s true. This tall species is usually covered with fine white hairs, which protect it from the hot sun and help it retain moisture to survive the harsh conditions of the desert.
The foliage is green, but depending on the degree of pubescence can appear silver or grey. The leaves are mid-sized and lanceolate to ovate.
Clusters of green and white flowers top the tall stems, with each flower having a reflexed crown.
Heartleaf Milkweed
Heartleaf milkweed features showy heart-shaped leaves on purple stems alongside pale pink flowers with deep pink-purple sepals.
This very showy and attractive milkweed species grows on the West Coast of the United States and is only native to California, Nevada, and Oregon. Despite its limited native range, it is quite popular for its ornamental appeal.
As the name heartleaf milkweed implies, the large leaves are heart-shaped and arranged opposite one another on purple stems. The leaves can sometimes take on the same purple hue.
The flowers hang in peduncles at the top of stems and have a slight weeping habit. Five deep pink-purple sepals open to small, pale pink flowers. This species is low-growing and is usually found in rocky areas of woodlands and forests. It blooms in its second year, in spring and summer.
Narrowleaf Milkweed
Narrowleaf milkweed is an excellent species for butterfly gardens and features large lavender and white nectar-rich flowers.
One important species for butterflies native to the Western United States is narrowleaf milkweed. This valuable food source for migrating monarchs is fast to colonize and very adaptable in terms of soil, water, and heat. It establishes and grows quickly, making it a great choice for the butterfly garden.
The flower clusters are large (4”-5” across) and upright on narrow stems with long, pointed leaves. The star-like individual flowers are lavender and white with a reflexed corona. These flowers produce a lot of nectar and are very popular among butterflies, bees, and hummingbirds.
Poke Milkweed
Featuring an attractive weeping appearance, poke milkweed thrives in diverse soils.
Poke milkweed has a unique and beautiful weeping appearance, with large, attractive leaves borne to either side of an unbranched stem. This variety is not picky about soil types and is happy in sandy soils of varying pH. As long as there is good drainage, poke milkweed will be happy.
The pedicels of flowers weep downward like so many tiny, shooting stars. The light green, star-like petals fold backward, revealing white hoods.
The flowers on this species are noteworthy, not only for their weeping quality, but they also contain a large amount of nectar and have a pungent and sweet aroma.
Prairie Milkweed
Prairie milkweed is a garden-friendly plant with an attractive appearance, smooth leaves, and fragrant pink flowers.
This pretty plant likes full sun and moist, rich soil conditions. It spreads by rhizomes but is less aggressive than common milkweed, making it a great garden plant. This species has a similar appearance to common milkweed, and in most respects, they are very similar.
Prairie milkweed is a moderate-sized species with sturdy stems that commonly branch toward the upper ends. The leaves are smooth and elliptical, with a central vein that can be pink, white, or green.
The flowers are deep orchid pink to lavender and very fragrant. This species is also larval food for the milkweed leaf-miner fly, so this little plant gets a lot of attention from insects.
Rush Milkweed
This milkweed species is a unique desert plant with stiff stems, bearing leaves only after rain.
Rush milkweed is a desert plant with some unique characteristics. It comprises many stiff stems that rise from the plant’s crown.
The interesting thing about these stems is that they bear no leaves, except after periods of rain, when small leaves may appear, but these are inconspicuous. The stems are densely arranged, and the flower umbels appear at the top.
This milkweed species is also a larval food for queen butterflies, so it is an extra vital cultivar to maintain. The flowers are light yellow to white and form terminal clusters followed by smooth seed pods.
This is one of the few evergreen varieties of milkweed, so it is very important to overwintering pollinators. It is also an exceptionally tall species.
Showy Milkweed
Showy milkweed has blue-green foliage and attractive pink and white star-shaped flowers that grow in spherical clusters.
This highly ornamental milkweed species is native to most of the central and western United States. It has a large range and makes a wonderful addition to the flower or butterfly garden.
The plant is mid-sized, reaching 1-3’ tall at maturity. With lovely, flocked, blue-green foliage, the plant is pretty enough without the flowers.
Showy milkweed’s flowers are stunning. Small pink and white, star-shaped flowers bloom in spherical clusters at the top of tall stems. Typically, they have dusty pink buds that open to mostly white, fragrant blooms, but the pink sepals will remain, creating a wonderful pink glow from within.
Swamp Milkweed
This tall and attractive species blooms pink flowers throughout summer and fall.
Swamp milkweed is a very important species, as it is naturally occurring in most of the United States, and it blooms throughout the summer and into the fall, when monarch butterflies are preparing to migrate for the winter. It also happens to be a very attractive and tall species of milkweed.
This species has tall, upright stems with olive green, lanceolate leaves. The stems are tinged with pink, and at the top, bright pink flowers bloom in umbels for a long period.
Everything about this plant is pretty, from the stems to the foliage, especially the pretty pink blooms. Even the seed pods this species produces are attractive and enticing to butterflies. It also has excellent cold and heat tolerance, with a wide range of zones where it will grow.
Tall Green Milkweed
The flower clusters grow all the way up the stems of tall green milkweed, giving more space for butterflies to pollinate.
Tall green milkweed is a very eye-catching species that is excellent for attracting butterflies. The formation of flower umbels intermittently along the tall stems is unique, as most species form flowers only at the top of stems.
Velvetleaf Milkweed
As the only milkweed species to tolerate saltwater, velvetleaf milkweed is vital to monarch butterflies migrating through Florida.
Possibly the most significant species of milkweed for monarchs in the state of Florida is velvetleaf milkweed. Every year, thousands of monarch butterflies appear in the coastal panhandle of Florida, pausing before they make their long journey to Central Mexico, where they overwinter. This takes place in October and November, and as a butterfly enthusiast, it is spectacular to behold.
Velvetleaf is important because it is the only species of milkweed that can tolerate salt water. This sturdy plant has tall, unbranched stems flanked with stiff leaves that have a flocked texture to their surface, to which their name is an homage.
The flower clusters are borne atop these stems. Flowers are pale green, occasionally with purple accents. This species is not available commercially and is endemic to Northern Florida.
White Milkweed
White milkweed features variegated flowers and deep green foliage, attracting diverse pollinators with its aromatic nectar.
Also called redring milkweed, white milkweed is native to the Eastern US coast and ranges inland as far west as Texas and Illinois. The scientific name of this species might seem a bit misleading when you see the plant, but the word variegata refers, in this instance, to the flowers rather than the leaves.
This species is very durable and tolerant of drought and prefers partial shade, as opposed to full sun, like most of its relatives. The foliage is deep green, strikingly contrasting the milky white flowers. The interior of the flowers is deep purple. They are strongly aromatic, which helps draw pollinators of all kinds to their ample nectar supply.
Whorled Milkweed
Whorled milkweed forms colonies with delicate foliage, thriving in dry, rocky soil and showcasing lacy white flower umbels.
This small, late-blooming milkweed is rhizomatic and forms lovely small colonies of delicate foliage and flowers. The thin, needle-like leaves whorl around a central stem in a loose rosette, giving this pretty plant its nickname.
Whorled milkweed likes dry, rocky, and sandy soil types. Its thin foliage adds a beautiful texture to the landscape, and its bright green pods stand up tall from the top of the stems. Before the pods form, the blooms are arranged in white, lacy umbels of tiny, delicate flowers.
Woolypod Milkweed
The wooly appearance of this species is due to the fine white hairs that cover the plant.
A soft coating of fine white hairs is what gives this milkweed its name. Both the leaves and pods are fuzzy, giving them a grayish-green appearance.
While the hairs on the leaves are shirt and soft, the hairs on the pods are longer. This variety likes well-drained soil and a dry environment and can tolerate a variety of soil types.
The flower clusters contain many small, cream-colored flowers. The petals fold backward, and the hoods stand out beyond them. These flowers have a slight waxy scent and bloom from spring through fall, making them a great addition to the flower garden or butterfly garden.
Zizotes Milkweed
Zizotes milkweed is a good species for attracting butterflies to your garden, especially if you live in a dry climate.
Our last species is one that you’ve probably not seen, in the wild or otherwise, but it has such a fun name and some unique traits that it deserves a mention. It is a small plant, remaining close to the ground. The foliage is denser than most milkweeds and has a silvery cast.
The flowers are unique in that they form close to the stem and in between leaves as opposed to an independent cluster. The pale green blooms have a hood that extends past the stigma and flares at the ends. It does well in dry climates but will produce more leaves and flowers following rain.
One to Avoid:
Tropical Milkweed
This species harms monarchs due to its non-native status, potential parasite transmission, and interference with reproductive cycles.
Tropical milkweed is common in nurseries across most of the country. The plant is banned in California, but most people still recognize it as the most familiar type of milkweed. However, it is not native to the United States, and it is not beneficial to monarchs during the portion of their migration that takes place here.
This tall, leafy, upright plant with gold and crimson flowers certainly is pretty, and it is a robust and vigorous grower, but it is not the best thing to plant in North American gardens. Tropical milkweed is particularly detrimental in climates where it is evergreen, zones 8-11. A parasite called Ophryocystis elektroscirrha can travel with monarchs and overwinter on these plants, reproducing and harming the monarch population.
There is also reason to believe that this particular type of milkweed, while it is a viable and suitable food source for monarchs in the spring, is not the ideal source for them in the fall, as it can interfere with their reproductive cycles.
Final Thoughts
With 73 species native to the United States, there are more than enough types of milkweed plants to suit every garden. These plants are great nectar producers, helping to sustain the populations of many pollinating insects. Their existence as larval food for monarchs is of great importance, and sustaining this plant is paramount in the preservation of this most recognizable of butterflies.
