Tag: Monarch Butterflies

Categories
native plants Pollinator gardening

Summer Blockbusters

Plants preferred by Pollinators and other Excellent Insects

Here in the Great Lakes Region, July and August are the peak of summer!  Gardens are growing and blooming.  Bees, butterflies, wasps and all are flying and working hard.  Now is the time to have a banquet ready for those hungry mouths.

On Mountain Mint

In this blog, I’ll present 5 plants that grow well and are true pollinator magnets in my garden.  Each of these has its own full blog but deserves a shout out for exceptional services.  I have them all and truly appreciate the cloud of insects drawn to them.

Virginia Mountain Mint (Pycnanthemum virginianum) and Wild Bergamot (Monarda fistulosa) begin blooming first.  Both are members of the mint family—Lamiaceae.  They produce abundant supplies of pollen and nectar for pollinators and beneficial insects. With both, you provide for long and short tongued insects.  For the gardener, their fragrant foliage tends to keep deer, rabbits and other herbivores away.(https://wildthingsinthe.garden/2023/05/31/white-goes-with-everything/ , https://wildthingsinthe.garden/2023/07/31/the-gardens-super-station/)3

Mountain Mint draws diverse pollinators.  From 2012 until 2015, the Penn State Southeast Agricultural Research and Extension Center performed a study looking at number of visits and types of pollinators visiting 86 native plants.  Clustered Mountain Mint (P. muticum) had the highest number of visits and most variety group of insects—bees, butterflies, wasps, syrphids, and tachinid flies.  Virginia Mountain Mint is a closely related plant.3

Wild Bergamot supports predatory wasps, bumble bees, butterflies, hawk/hummingbird wasps, a number of specialist bees and hummingbirds.  The Xerces Society for Invertebrate Conservation recommends it in their Monarch Nectar Plant Guide-Midwest and where its native.  It’s easy to grow from seed and can be planted on bare soil in the spring.  

Monarda fistulosa is a favorite of hummingbird.  Red or orange flowers are often recommended for hummingbirds.  In my experience, these winged wonders do explore red things.  But they find nectar in lavender, pink and even blue native blooms!

Culver’s Root (Veronicastrum virginicum) spans between July and August.  Beginning in mid-July, these white to pink spires open from the bottom to the top.  The individual florets provide pollen and nectar for short and long tongued bees.  Sweat bees, small and large carpenter bees, leaf-cutter bees, long-horned bees, bumble bees and lots of honeybees visit Culver’s Root.(https://wildthingsinthe.garden/2023/06/30/the-garden-by-candlelight/)4

In the original post, I didn’t mention the June haircut.  V. virginicum absolutely benefits from the haircut.  The deer taught me this lesson.  They ate half my plant and left the rest.  The damaged part grew and flowered.  It was shorter than the other half but didn’t flop.  The other half bloomed but flopped.  Put this one on the list for a trim.

In the first week of August, only the very last florets of Virginia Mountain Mint and Wild Bergamot are open.  Culver’s Root has about 1/3 of the spire still open.  Joe-Pye Weed (Eutrochium purpureum) and Cut-Leaf Coneflower (Rudbeckia laciniata) take center stage.( https://wildthingsinthe.garden/2024/10/31/a-fabulous-fuzzy-flower/, https://wildthingsinthe.garden/2025/10/02/green-eyed-starbursts/)

Joe-Pye Weed begins opening toward the end of July.  By early August, it’s swarmed with butterflies, bumble bees, honeybees, large and small carpenter bees, mining bees, leaf-cutter bees and sweat bees-metallic and halictid.  In addition to supplying pollen and nectar for late season insects, E. purpureum is a larval host for various moths.

Joe-Pye Weed also benefits from the June haircut.  I’ve noticed my plants in part-shade/shade bloom later than those in full sun.  This gives my garden an extended season.  Also, this plant can overgrow moist, sunny spaces.  It’s better to pull early and often to control it in the rain garden.

At the beginning of August, Cut-Leaf Coneflower blooms have just begun opening.  Rich in resources, this plant is especially beneficial to native bees and honeybees including bumble bees, metallic and halictid sweat bees, and large carpenter bees.  Adult butterflies, moths, and skippers nectar at R. laciniata.  While Common Eupithecia (Eupithecia miserulata), Wavy-Lined Emerald Moth (Synchlora aerata), Southern Emerald Moth (Synchlora frondaria) and Silvery Checkerspot Butterfly (Chlosyne nycleis) use it as a larval host.  Monarchs and other butterflies nectar from the flowers.2

My favorite thing about this plant is Goldfinches.  Once it goes to seed, the finches cover it.  Even in plants with some flowerheads and some seedheads, I see them.  I have it right outside the kitchen window where I can watch all the fun. 

But a note of caution:  all those seeds mean lots of seedlings.  Cut-Leaf Coneflower is another plant to pull early and often.  Possibly find a location where it can be confined.

These plants or a combination of them could be used to establish a wildlife habitat with containers.  With pots, a balcony or a tiny back patio becomes a haven for pollinators.  Everyone can enjoy these beautiful plants and the pollinators that follow!

24 years ago, when I start using native plants, no one knew much about using them in a garden setting much less in pots. Now, numerous sources provide information for anyone whose interested.  I’ve listed several good ones in the bibliography for reference.  But here are some highlights.1,5,6  

Native plants usually have deep roots so wide and deep pots are best—at least 16 inches.  A variety of container materials works well.  Terra cotta or ceramic drains well and dries quickly. Useful for plants that need good drainage.5,6  

Unfortunately, it doesn’t survive severe freeze/thaw cycles.  Terra cotta/ceramic containers would need to be brought inside where is stays above 32oF or protected from freezing in some other way.6

Fiberglass, recycled plastic and/or metal all do better with overwintering.  They’re also lighter and retain water longer for less watering.  Beware of metal in direct sun and heat.  It’s too hot for most plants!6

For soil, a good quality potting mix will do.  Organic mix is usually preferred.  But if unavailable, add some compost to the soil.  If lighter, quick drainage soil is needed, add sand and vermiculite.5,6  

When choosing plants, the National Wildlife Federation (NFW) recommends using plants that survive 2 zones below your location.  The difference protects them during the winters when they don’t have the ground for insulation.5  

Calculating the zones.  For example, I’m in zone 6.  Wild Bergamot (Monarda fistulosa) is hardy down to 3.   3 zones colder than mine and Wild Bergamot is an excellent choice for a container.  Here is a link to look up hardiness zones by zip code:  https://planthardiness.ars.usda.gov.  Plant should still be native to your region.5

It’s possible to insulate containers at planting.  For areas of extreme cold, line the inside of the pot with pieces of Styrofoam.  Containers can also be covered with tarps.6  

Wild Bergamot and Cut-Leaf Coneflower seed abundantly.  Plants that reseed tend to survive the freeze/thaw cycle better.  The seeds are insurance in the spring that something will grow.6

Finally, container plantings with “nurse” plants seem to survive better.  Nurse plants provide structure above and below ground.  Above, they give a layer of dead material to cover the surface.  Below, the roots keep the soil structure in place.6

So, what if you want to grow Joe-Pye Weed or Culver’s root in a container?  Culver’s root has a long, fibrous taproot that helps it survive drought on its native prairie.  Taproot plants are not good candidates for containers.

Joe-Pye Weed doesn’t have a taproot but it’s tall.  Sometimes a very large pot works.  But what about cultivars?7

Cultivars are controversial in the native plant community.  Native plants are guaranteed to work with the insects and other creatures they evolved with.  This is especially true for specialist insects both caterpillars and bees.  These insects interact with plants at a molecular level.  They can usually sense genetic differences.

But there’s no arguing that natives have drawbacks.  Whether it’s their size, their habit (i.e., tendency to flop) or how quickly they spread, horticulture often looks for change.  The Xerxes Society for the Preservation of Invertebrates mentioned several key points when considering native cultivars or nativars:

  1.  Look for flowers that are the same color as the native.  If it’s just bred for more flowers that’s OK.
  2. Flowers can’t have double or more petals. Double flowers have less or no pollen and pollinators can’t reach the nectar.
  3. Foliage color should also be close to the straight species.  Larvae and other leaf eating insects often won’t eat different colored foliage.7

Back to the Joe-Pye Weed question.  Two smaller nativars are available.  Little-Pye (Joe-Pye Weed) at 12” to 14” and Baby Joe (Joe-Pye Weed) at 2’ to 3’.  Both have bloom and foliage color like the native plant and are suitable for containers.  So far, so good.7

But these 2 plants highlight another difficulty with cultivars.  If you look closely at the catalogue’s plant name, the scientific name is Eupatorium dubium not Eutrochium purpureum.  First, that’s the former name. The new Latin name is Eutrochium like Eutrochium purpureum.  This is not uncommon.  Customers get used to one name and catalogues are reluctant to change.  

The second issue is more concerning.  E. dubium is native to the Eastern coastal region not the Great Lakes ecosystem.  Customers need to decide if native to North America is close enough.

More about names, the common names used for nativars can be related to marketing, not historical common names.  For example, Chocolate Joe-Pye Weed is a cultivar of Ageratina altissima or Snake Root.  Another native plant but I guess Chocolate Snake Root wasn’t as appetizing!

Finally, the American Meadows catalogue provided the complete Latin names.  But I have seen tags where only the genus (i.e., Eupatorium) is provided and sometimes not even that.  Overall with nativars, it just hard to tell what you’re getting.

Another option is to choose another closely related plant.  Boneset (Eupatorium perfoliatum) is smaller than Joe-Pye Weed and can adapt to containers.   Like Joe-Pye Weed, it needs regular watering to maintain average soil moisture.  But with its fuzzy white flowers, insects of all kind love it.

I hope you’ve enjoyed revisiting the 5 pollinator powerhouses for summer!  Individually or in combination, they bring the nutrition the bees and others need.  Adding containers is a great option for small spaces or just to add some plant you can’t fit in the garden!

Happy Gardening,

Mary

BIBLIOGRAPHY

  1. “Container Gardening with Native Plants.” n.d. Accessed August 16, 2026. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/visual-guides/container-gardening-with-native-plants.
  2. Kanitz, Amalia. “Rudbeckia – Native Plant of the Week – Fruition.” 07/07/2025. Accessed August 15, 2026. https://blogs.cornell.edu/fruition/2025/07/07/pg-rudbeckia/.
  3. “Mountain Mint: A Pollinator Powerhouse.” n.d. Accessed August 15, 2026. https://extension.psu.edu/mountain-mint-a-pollinator-powerhouse.
  4. Michigan State University Extension. n.d.  “Culver’s Root, Veronicastrum virginicum (L.) Farw.”  Native Plants and Ecosystem Services. Accessed August 16, 2026.  https://www.canr.msu.edu/nativeplants/plant_facts/culvers_root.
  5. National Wildlife Federation. n.d. “Native Plant Container Gardening | NWF Native Plant Habitats.” Accessed August 16, 2026. https://www.nwf.org/Home/Native-Plant-Habitats/Plant-Native/Small-Space-Wildlife-Gardening/Container-Gardening
  6. Ressing, Sara. 2025. “Native Plants for Urban Balconies.” Wild Ones: Native Plants, Natural Landscapes, March 10. https://wildones.org/native-plants-for-urban-balconies/.
  7. Xerces Society. n.d. “Picking Plants for Pollinators: The Cultivar Conundrum.” Accessed August 16, 2026. https://xerces.org/blog/cultivar-conundrum.
  8. Xerces Society. n.d. “Plants for Pollinators: Wild Bergamot.” Accessed August 15, 2026. https://xerces.org/blog/plants-for-pollinators-wild-bergamot.
Categories
native plants Pollinator gardening

Fiery Flowers for Sunny Spaces

Vibrant orange blooms glow against lush green leaves.  Thriving in sunny, dry spots, Butterfly Milkweed (Asclepias tuberosa) calls insects of all kinds—bees, wasps, flies, beneficial insects and butterflies.  It also hosts caterpillars for some butterflies and moths.

Butterfly Milkweed grows in Zones 3 through 9.  It reaches between 1 and 3 feet and spreads from 1 to 1.5 feet.  Its size makes it an excellent choice for the home garden.3,4

The best growing conditions include full to part sun.  It flourishes in sandy or rocky, acidic soil.  With good drainage, this plant tolerates other soils including loam and clay.3.4

Asclepias tuberosa lives in high quality natural areas and in disturbed places.  It’s found in upland sand prairies, hill prairies, cemeteries, open prairies, sandy savannas, open rocky woodlands, shale and sandstone glades, abandoned sandy fields, roadside embankments, areas along railroads and dry, open, rocky woods.  I primarily see it on roadside embankments.4

Unlike other milkweeds, Asclepias tuberosa’s leaves are closely spaced on the stem. The oblong leaves emerge alternately from the stem and have pointed tips.  They’re sessile (attached to the stem) or have short petioles (less than an 1/8 inch).4  

 The upper side of each leaf is medium to dark green and smooth or maybe with a few hairs.  The lower side is light to light medium green and covered with short hairs.  Foliage is 2.5 to 3.5 inches long and 0.5 to 0.75 inches wide.  This milkweed lacks the white-milky latex that gives milkweeds their name.  Its sap is clear and watery.4

Butterfly Milkweed’s flowers are striking.  While I was looking through my photos, every picture of it jumped out immediately because of that distinctive orange color.  Blooms arise from the upper stem and axils of the upper leaves. 

Individual umbels (groups of florets) are 1 to 2.5 inches across.  They’re made up of 8 to 25 blooms.  Slightly domed, umbels often grow next to each other.  Groups of umbels form composite flowerheads 2 to 5 inches across.4

Individual flowers have the classic milkweed composition-5 petals, 5 hoods with horns and a central reproductive column.   The central column is called a gynostegium.  It’s composed of modified male and female floral parts.  For a full explanation of milkweed reproduction, see my blog (A Delicate Pink Star, https://wildthingsinthe.garden/?s=Common+Milkweed).4

Blossom color naturally ranges from reddish orange to yellowish orange.  Bloom time runs from early to midsummer.  If deadheaded, A. tuberosa reblooms in late summer to early fall.  The flowers are long lasting although they have no noticeable fragrance.3,4

Butterfly Milkweed’s root system is the secret to its survival in dry conditions.  Thick and knobby, the tap root can grow several feet down.  One- to two-year-old plants have a generous tap root—2-3 inches long and 0.5 to 0.75 inches wide.  This root helps its survival but makes it difficult to transplant.  Generally, direct seeding works best.4

In addition to drought, Butterfly Milkweed resists deer, erosion, dry soil, shallow, rocky soil and has moderate salt tolerance.  Unfortunately, in wet, poorly drained soil conditions, it’s susceptible to crown rot, rust and leaf spot.4

Asclepias tuberosa is a wonderful plant for a dry spot in the garden.  The orange flowers catch the eye.  They also offer some variety from the usual yellow or white flowers found on summer-blooming native plants.  

Butterfly Milkweed has received a variety of awards.  These include Missouri Botanical Garden’s Plant of Merit, North Carolina Wildflower of the Year 1985 and Perennial Plant of the Year 2017.  All recognize that this milkweed is easy to grow, resistant to pests and disease and ornamental in the garden.1,2,5

As a native plant, Asclepias tuberosa entertains and feeds numerous native pollinators and beneficial insects.  It serves as a larval host for butterflies.  The Ruby-Throated Hummingbird drinks nectar from the blooms.4

The Xerces Society for Invertebrate Conservation has declared Butterfly Milkweed of Special Value to Native Bees, Special Value to Bumble Bees, Special Value to Honeybees and that it Supports Conservation Biological Control.  A variety of bees visit its brilliant blooms.  These bees include:  Honeybees (Apis spp.),

Bumble Bees (Bombus spp.),

Large Carpenter Bees (Xylocopa spp.),

digger bees (Melissodes spp.), leaf-cutter bees (Megachile spp.),

small resin bees (Heriades spp.), Halictid bees (including green metallic bees)

Lasioglossom spp. ,

Augochlora pura,

and small carpenter bees (Ceratina spp.).3,4

Heriades spp. or small resin bees gather pollen from Butterfly Weed, carrying it on their abdomens.  These bees build their nests in existing spaces or cavities in wood or hollow stems.  They gather resin from plants to separate each nest cell.6

When building a nest in a long cavity, Heriades spp. often leaves a vestibule or space before the first nest cell.  She seals this space with a resin wall and begins making brood cells.  When the nest is closed, the small resin bee leaves another space between two resin plugs.  

Nesting begins in late spring to early summer.  Female offspring regularly outnumber males. They are usually laid at the back of the nest.6  

 These Small Resin Bees pollinate various native plants including Tickseed (Coreopsis spp.), Milkweed (Asclepias spp.), Wild Bergamot (Monarda fistulosa), Sunflower (Helianthus spp.), Coneflower (Ratibida spp.), Ironweed (Vernonia spp.) and Nodding Onion (Allium cernuum).  There are reports of Heriades happily pollinating onions and leeks.6

In addition to bees, Thread-Waisted wasps (Ammophila spp.) and other Sphecid Wasps gather nectar from Asclepias tuberosa.

Living up to its name, Butterfly Milkweed feeds a variety of butterflies.  Fritillaries (Speyeria spp.), Swallowtails (Papilio spp.) and the Monarch (Danaus Plexippus).  

It’s also a larval host for the Monarch Butterfly (Danaus Plexippus), the Queen Butterfly (Danaus gilippus) and the Gray Hairstreak Butterfly (Strymon melinus).4

The Grey Hairstreak Butterfly (Strymon melinus) is in the Lycaenidae family and is one of the Gossamer wing butterflies.  They are pale grey with bright orange eyespots at bottom edge of their wings.  Near the eyespots, are very thin tails coming off the hindwings—one on each wing.  These tails inspired the common name Hairstreaks.5  

Many butterflies and moths have eyespots on the upper surface of their wings.  It’s thought that they startle predators while the butterfly/moth flies away.  This kind of adaptation is called mimicry.  The eyespots mimic eyes, perhaps even those from another species–like an owl.  

The Grey Hairstreak has a slightly different take on it.  Its eyespots are on the bottom of the wings so they’re visible when it’s perching.  The 2 antennae-like tails located next to the eyespots highlight the appearance of a second head.  This butterfly even moves its hindwings up and down to imitate antennae twitching.5  

If a predator strikes the eyespot, the butterfly has a chance to get away.  No doubt, this works on large predators like birds.  It also fools the jumping spiders often found on flower heads.  The spiders aim for their prey’s head.  Once there, they inject venom into the butterfly’s thorax.  When the jumping spiders land on the eyespots, there are no convenient body parts to bite!

As if this weren’t amazing enough, Lycaenid caterpillars have a special relationship with ants.  I know ants are hard to love.  I, myself, declare a red alert when I see one in the house.  Yet, I have come across some wonderful things ants do for the ecosystem.5

For Strymon melinus, ants tend the larvae in a myrmecophilous relationship.  In return, the caterpillar feeds the ants and gives off an alarm pheromone-like chemical.  Since the ants get something in return, it’s a mutualistic relationship.

Grey Hairstreak larvae make a sweet liquid in the dorsal nectary organ on their seventh abdominal segment.  Ants harvest the liquid from this “honey gland.”  In return, they tend the caterpillar and protect it from predators.  These Strymon melinus larvae vary in color.  They can be pale yellow, purplish-white, pink, reddish-brown or green.  Some sources say the green larvae are so well camouflaged that it’s easier to follow the ants.5.7  

In addition, the larva has a tentacle organ that gives off a chemical.  This compound is like the ants’ alarm pheromone.  When the ants’ smell it, they become alert and protective.  An alternate suggestion for these behaviors, they keep the ants from preying on the caterpillars.5

Hope you enjoyed this exploration of  Butterfly Milkweed and some of the creatures that visit it.  Enjoy the coming Spring weather!  I hope you have plenty of time to spend in your garden.

Happy Gardening,

Mary

Bibliography:

  1. “Asclepias Tuberosa – Plant Finder.” n.d. Accessed November 15, 2025. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b490.
  2. “Asclepias Tuberosa (Butterfly Milkweed, Butterfly Weed, Chiggerflower, Common Butterfly-Weed, Indian Paintbrush, Milkweed, Pleurisy Root) | North Carolina Extension Gardener Plant Toolbox.” n.d. Accessed November 15, 2025. https://plants.ces.ncsu.edu/plants/asclepias-tuberosa/.
  3. “Asclepias Tuberosa (Butterflyweed) | Native Plants of North America.” n.d. Accessed November 15, 2025. https://www.wildflower.org/plants/result.php?id_plant=astu.
  4. “Butterfly Milkweed (Asclepias Tuberosa).” n.d. Accessed November 15, 2025. https://www.illinoiswildflowers.info/prairie/plantx/btf_milkweedx.htm.
  5. “Butterfly Weed | Chicago Botanic Garden.” n.d. Accessed November 16, 2025. https://www.chicagobotanic.org/plant-information/plant-profiles/butterfly-weed.
  6. “Gray Hairstreak Butterfly.” 2019. Field Station, April 17. https://uwm.edu/field-station/bug-of-the-week/gray-hairstreak-butterfly/.
  7. Holm, Heather. 2017. Bees:  An Identification and Native Plant Forage Guide. Pollination Press LLC.
  8. iNaturalist. n.d. “Gray Hairstreak (GTM Research Reserve Butterfly Guide) · iNaturalist.” Accessed March 5, 2026. https://www.inaturalist.org/guide_taxa/358983.
Categories
native plants Pollinator gardening

A Summer Cornucopia

Common Milkweed or Asclepias syriaca is a superb Monarch support and a mainstay of Monarch waystations.  But it is so much more.  This plant feeds more than 450 insects at different life stages. Diverse insects consume nectar, sap, leaves, flowers and seeds5.  Admittedly weedy, its lovely blooms are fragrant and enhance any scent garden1,5.

Common Milkweed thrives in full sun and well-drained soils.  Like other “weeds”, it’s not picky about growing conditions.  A. syriaca  grows in clayey, sandy or rocky calcareous soils, loamy soils and high clay or sand soils. 

Asclepias syriaca springs up in disrupted areas.  Human activity disrupts natural areas.  But natural disruptions occur where water rises and falls, for example, along streams and lakes.  

In nature, Common Milkweed is found in moist and dry black soil prairies, sand prairies, sand dunes along lake shores, fields, pastures, abandoned fields, vacant lots and along railroads, fence rows and roadsides. 

Common Milkweed absolutely lives up to its weedy name.  It spreads by seed and by long creeping rhizomes that pop up in unexpected places.  Once established, this plant is extremely difficult to remove. 

These habits are offset by Common Milkweed’s value to insects and pollinators.  It’s best to let it grow where you don’t mind its vigorous and abundant nature—a wild area, a meadow or a prairie garden.

Asclepias syriaca offers a strong erect form in the garden.  The pale, cylindrical central stem supports opposite jade-green leaves.  These leaves range from pale to dark green on top and are pale green with short, dense hair underneath.  Each leaf has a distinctive central vein with small veins spreading to the edges.  

The milky sap, which gives Milkweed its name, oozes whenever part of the plant is broken.  The sap is called a latex and contains 2% latex.  The latex is thick and sticky.  

Most ingeniously, caterpillars will reduce the sap’s flow by taking tiny bites closer to the stem.  The sap leaks out there.  When the caterpillar begins to eat a leaf, there’s less latex at the feeding site.  Thus, less chance the sticky stuff will foul the larva’s mouth2,3.

For humans and other mammals, there are other concerns.  The milky sap contains cardenolides, specifically cardiac glycosides.  Contact with the skin or eyes causes irritation.  If eaten or exposed to mucous membranes, cardiac glycosides can disrupt the nervous system, the kidneys, the muscles (which includes the heart) and the human’s/animal’s acid/base balance3,4,5.  

The monarch and other insects that consume milkweed have turned this to their advantage.  As the caterpillars/insects consume milkweed their bodies store the cardiac glycosides.  If a bird or animal eats them, they taste bitter and can make the predator feel sick.  

Predators soon learn to leave them alone. The orange/black or red/black coloring of milkweed insects signals, “Stay away!  Not good for you!”  The technical term for this warning coloration is ‘aposematic’5.

Milkweed blooms don’t dazzle but flower in 1930’s vintage shades.  The drooping balls of florets are soft and dusky lasting one to one and a half months.  Colors range from greenish white to greenish pink to rosy-pink to purplish-pink to reddish purple.  

Each cluster averages 30 individual florets but can have up to 100. Their sweet, vanilla fragrance drifts from the three to five umbels on each plant.  

Up close, each floret is a fascinating feat of engineering all directed toward an exceptional pollination system.  Each a quarter of an inch across, the florets have five reflexed (bent back) petals and five raised hoods with curved horns.  The hoods have lighter colors than the petals.  

In the center of each floret, is a cylindrical structure formed by two fused stigmas.  It’s called the stigmatic column.  

Between the hoods, are the stigmatic slits.  These slits hold the pollinaria.  Unique structures, pollinaria hold waxy sacs of pollen.  These are transferred instead of the loose, powdery pollen used by most flowers.  Milkweeds and orchids are the only known plants to have them6,7.

The milkweed pollinium (or pollinarium) consist of a blackish-brown oval gland (corpusculum) with a slit, two translator arms hanging from the gland and two pollinial sacs.  Before each sac, a knee bend of approximately 900 occurs in the arm.  This bend enables the rotation of each sac during pollination.

In the milkweeds, the pollinial sac sit inside the stigmatic column and only the corpusculum is visible between the hood structures.  When an insect lands on the flower, one of its legs may slip into the stigmatic slit between two hoods.   As it tries to free itself, the leg moves upward toward the slit in the corpusculum. Bristles in the chamber keep it from going back down.  

Insects must be strong to free themselves.  Large butterflies, predatory wasps and long tongue bees are most likely to remove pollinaria.  Lost legs and dead smaller insects both occur from failed escape attempts.

When a pollinaria is removed, it begins to dry.  The pollinial sacs rotate 90o during drying.  The rotation moves them into the correct position for pollination.  

When the insect lands on another milkweed,  the knee bend (not the corpusculum oval) slides into the space between the hood petals.  The translator arm follows then the rotated pollinial sac.  The pollinial sac slides into a space in the stigmatic column and pollination is completed.  

When the insect continues pulling upward, the translator arm breaks.  The insect keeps the remaining part of the pollinaria.  

It’s also possible to start a chain of pollinaria during this process.  As the broken translator arm slides between the hoods, it can hook the corpusculum slit of this floret’s pollinaria adding a fresh pollinaria to the partial remaining one.  Clumps and chains of all sorts develop this way.  These groups of pollinaria may increase chances of pollination6.7.

Part I, ends here, with the exciting conclusion of a fertilized milkweed.  Part II will continue with photos and information about the insects that use Common Milkweed.  What a crowd it is—including flies, wasps, bees, butterflies, moths, skippers, plant bugs and beneficial insects!

See you next time to discover what Wild Things are in the Garden!

Mary

References

  1. Hilty, J., n.d., Common Milkweed, Asclepias syriaca, Milkweed family, (Asclepiadaceae),  https://www.illinoiswildflowers.info/weeds/plants/cm_milkweed.html
  2. Berkov, A., 28.October.2010, Plant Talk:  Inside the New York Botanical Garden; Plant Profile:  The Extraordinary Common Milkweed, How Do Insects Feed on this Plant with Sticky White Latex? https://www.nybg.org/blogs/plant-talk/2010/10/science/plant-profile-the-extraordinary-common-milkweed/#:~:text=Plants%20in%20the%20genus%20Asclepias,Asklepios%2C%20the%20ancient%20Greek%20physician.
  3. Bowe, Scott, 11.September.2018, Milkweed is More Than Just a Common Weed, WXPR, https://www.wxpr.org/natural-resources/2018-09-11/milkweed-is-more-than-just-a-common-weed
  4. Nelson, M. and Alfuth, D., 24.February.2021, Milkweed (Ornamental Plants Toxic to Animals), X-number:  XHT1276, https://hort.extension.wisc.edu/articles/milkweed-ornamental-plants-toxic-to-animals/
  5. Taylor, David, n.d., Common Milkweed, (Asclepias syriaca L.), Plant of the Week, https://www.fs.usda.gov/wildflowers/plant-of-the-week/asclepias_syriaca.shtml
  6. Eldredge, E.P., 2015,11,00, Milkweed Pollination Biology, Plant Materials Technical Note NV-58, Natural Resources Conservation Service, https://www.nrcs.usda.gov/plantmaterials/nvpmctn12764.pdf
  7. Betz, R.F., Struven, R.D., Wall, J.E. & Heitler, F.B., 1994, Insect Pollinators 12 Milkweed (Asclepias) Species, T.B. Bragg and J. Stubbendieck (eds.) Proc. Of the Thirteenth North American Prairie Conference. Univ. of Nebraska, Lincoln, NE.

Categories
native plants Pollinator gardening

Sparks in the Garden

Every year in the early Fall, a glittering cloud of insects surrounds the arching stems of Solidago rugosa ‘Fireworks’.  Butterflies, moths, skippers, bees, wasps, beetles, beneficial insects, and flies all flock to this goldenrod for nectar, pollen and to use it as a larval host.  This feast helps prepare them for the cold months of winter.

The twinkling yellow flowers of ‘Fireworks’ goldenrod pop open along stems up to 18” long!  Held above the foliage, these stems resemble fireworks and give the plant its name.  Pompom blooms are tightly packed along the stems. Each one is about 1/8th inch in diameter.  The anthers are held above the stigmas and bright yellow ray flowers form the outer ring.  Peak bloom lasts two to three weeks.

Medium to dark green leaves grow alternately and are three to six inches long.  They range from ovate to lanceolate and their edges are toothed.  The deeply sunken veins in the leaves causing a wrinkled look. This feature gives them the name rugosa or wrinkled.  In fact, a common name for the native Solidago rugosa is Wrinkle-Leaved Goldenrod.

Solidago rugosa ‘Fireworks’ is a charming goldenrod cultivar.  Well-behaved, it sports abundant bloom for a grand show in the garden.  An erect plant, it forms dense clumps with slowly spreading rhizomes.  It grows three to four feet tall.  Spreading from two to three feet, ‘Fireworks’ will reseed if happy.  Space plants one to three feet apart.  

‘Fireworks’ thrives in zones four to eight.  It enjoys moist, well-drained soils although it can tolerate periods of drought or wet soil.  Highly adaptable to different soils, this goldenrod grows in clay, loam (silt), and sand as well as acid to neutral conditions. My plants have not been bothered by deer or rabbits.  It can withstand both heat and humidity. 

The genus Solidago, like Symphyotrichum, is an essential part of wildlife habitat, a keystone species.  In recent years, people have become interested in keystone species of all types.  A keystone species is one so crucial that the ecosystem will collapse without it.

How does this work with plants?  Key plants are native plants that are part of the local food web.  They play a role as a general or specific support for insects.  The general group are the 14% of native plants that support 90% of butterfly and moth Lepidoptera species.1  The specific group are the 40% of native plants that produce pollen for the 15% to 60% of North American native bee pollen specialists.1  Both these groups are listed in the Keystone Plants by Ecoregion from the National Wildlife Federation.  According to this information, Solidago sustains 104 species of caterpillars and 42 different specialist bees.2  (I have used the Eastern Temperate Forest list since this is my region.)  In addition to these categories, 145 different wasp species forage on Solidago.3

So, goldenrod offers abundant food at the end of the year, how is this valuable?  Fall is when next year’s insect generation is established.  Whether it’s healthy adults, well fed caterpillars or full provisions in nests, the foundations are laid with Autumn food harvest.  Goldenrod is one vital resource.

Different insects have different strategies for surviving the winter.  In the next few paragraphs, I’ll talk about what the pollinators do over the winter and where they might be.  Bumblebee and honeybee queens take mating flights in the late summer or fall.  Male bumblebees take advantage of nectar from Solidago ‘Fireworks’ to fuel up before pursuing their queen. When they’ve mated, the queens find a safe location to overwinter.  Some bumblebee queens hibernate in leaf litter and others burrow underground.4

Honeybee queens return to the hive.  During the winter, the honeybees form a ball in the hive.  If they become cold, they will vibrate for warmth.  The queen stays near the center of the mass.  Any resources gathered in the fall, are converted into honey, and used to help the honeybees survive the winter.5

Native bees overwinter as young in their nests.4  Active native bee queens use the resources from goldenrods to supply their nests.  Like Symphyotrichum, Solidago has numerous bee specialists including:  Andrena (Callandrena) asteris, A. (Callandrena) braceata,  A. (Callandrena) simplex, Andrena (Cnemidandrena) hirtcincta, Andrena (Cnemidandrena) canadensis, Colletes simulans, Colletes solidaginis, Perdita (Perdita) octomaculata and Melissodes (Eumelissodes) fumosus.

Where are their nests?  70% of native bees nest underground!  Now is not the time to start digging.  Others nest in old beetle burrows and other holes in dead wood and still others in hollow stems.4  It’s better to wait until spring to cut back dead stems and clean up dead wood.

Solidago rugosa ‘Fireworks’ attracts numerous native wasps.  Indeed, unlike asters, I find wasps visiting my ‘Fireworks’ goldenrod in equal numbers with the bees.  These wasps serve as beneficial insects preying on or parasitizing pests that damage plants.  They also contribute to pollination as they drink nectar and, occasionally, eat pollen.  Native wasps spend the winter in different ways:  some as mated females called foundresses, some as young and some we don’t know yet.  The foundresses find dry, warm spots to hide in.  Other nesting locations are similar to bees including stems, wood, underground and old nests built by other wasps or bees.3

Many flies visit ‘Fireworks’ goldenrod to drink nectar and, incidentally, pollinate the flowers. The larval stage of some Tachinid and Syrphid flies are beneficial insects. Tachinid flies parasitize leaf eating insects. They over winter in the larval or pupal stage often in the shell of their host. The larvae or pupae can be found in piles of leaves or bush or burrowed into the soil.

Syrphid fly larva are excellent early and late season predators. They consume dozens of aphids each day. Most spend the winter as pupae or larvae in dead leaves or piles of brush.

Butterflies use goldenrod for nectar.  Monarchs fuel up for their migration and other butterflies build fat stores to hibernate as adults.  Not all butterflies overwinter as adults,  they can spend the cold months as eggs, caterpillar, chrysalis, or adults depending on the species.  The eggs are laid close to a spring food source.  Caterpillars deliberately hid in curled leaves, soil or under rocks for protection.  If becoming a chrysalis, the caterpillar will choose a protected location, for instance, under an overhang or deep in a shrub.  Adult butterflies and moths are very diverse when hiding.  Spaces under bark, crevices in trees, cracks in rock and the fall leaves all host butterflies and moths.6

Solidago serves as a larval host for 104 butterfly and moth caterpillars.  One unusual moth is the Wavy-Lined Emerald.  The caterpillar has a fascinating adaptation.  It decorates itself with the leaves or flowers from its host plant.  This camouflage hides it from predators.  The twirler moths (Gelechiidae), Geometer moths, Owlet Moths (Noctuidae), and Tortrix Moths also use Solidago.

The take home for today: Leaves are not Litter!  Stems Stand Tall!  Don’t Do that Digging!

Just take a rest, drink some cider, and enjoy those Fall colors!

References:

  1. Keystone Plants by Ecoregion, The National Wildlife Federation, https://www.nwf.org/Garden-for-Wildlife/About/Native-Plants/keystone-plants-by-ecoregion
  2. National Wildlife Federation, Gardening for Wildlife, Keystone Native Plants Eastern Temperate Forests – Ecoregion 8, https://www.nwf.org/-/media/Documents/PDFs/Garden-for-Wildlife/Keystone-Plants/NWF-GFW-keystone-plant-list-ecoregion-8-eastern-temperate-forests.ashx?la=en&hash=1E180E2E5F2B06EB9ADF28882353B3BC7B3B247D
  3. Holm, H., 2021 Wasps:  Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants, Minnetonka, MN, Pollination Press LLC.
  4. Morris, S. (2018, October 10). Where Do Pollinators Go In The Winter? Xerces Society for Invertebrate Conservation.  https://xerces.org/blog/where-do-pollinators-go-in-winter#:~:text=Most%20native%20bee%20species%20will,help%20to%20survive%20until%20spring.
  5. Hogeback, J. Where Do Honeybees Go In The Winter?  Britannica.  https://www.britannica.com/story/where-do-honeybees-go-in-the-winter
  6. Grisak, A. (2022, November 04). How Does A Butterfly Survive Winter? Birds & Blooms. https://www.birdsandblooms.com/gardening/attracting-butterflies/butterflies-in-winter/