Tag: butterflies

Categories
Pollinator gardening

Furry Little Tails

Just as the snow disappear, the small bumps on Pussy Willow (Salix discolor) branches lengthen into soft, furry, gray catkins.  Soon they burst into bright yellow blooms before spring ephemerals and other early trees and shrubs.  Their nectar and pollen draw early bees, flies, wasps, adult butterflies and other insects. 4,9

 Later, this willow is a larval host to many butterflies, moths and skippers.  In addition, many insects feed on and/or use this plant.  The caterpillars and insects support an abundance of bird life especially during nesting season.9

Salix discolor thrives in zones 2 through 8.  It generally grows from 6 to 15 feet and spreads from 4 to 12 feet.  For a smaller shrub, cut it back every 3 to 5 years after flowering.  This pruning encourages lots of new growth.5,6

Pruning is especially important when Salix is growing in wet conditions.  Pussy willow forms suckers freely.  Cutting helps control the suckers also.5,6,7

Pussy willows love wet soils but do tolerate medium moisture soils.  They grow in sandy and non-sandy soils with around neutral pH and some decaying matter.  Salix discolor enjoys part to full sun.  They’re resistant to deer, erosion and Black Walnuts (Juglans nigra).5,6

Its natural habitats include soggy thickets, fens, wet prairies, low ground, floodplain forests, marshes, low areas along rivers and other bodies of water, ditches, and shrub swamps.  If too many trees grow, the Pussy Willows die out.9

Salix discolor has male and female flowers on different shrubs, also called dioecious.  Males are yellow with pollen, females are green. The specific epithet discolor comes from the two different colored flowers.  Blooms develop on second year twigs.7,9

The male bloom starts as a furry pearl-gray catkin.  The soft dense hairs protect the florets from the cold.  As they open, tight round stamens poke through the fur.  When the stamens are fully extended, the male blossoms turn bright yellow.  Each floret has 2 stamens. The catkin grows up to 1 inch long.9

Spikey and green, the female catkins mature from 1 to 4 inches long.  Each floret has 1 pistil with a pair of tiny stigmata at the top.  The pistil forms a narrow lance-like shape and had tiny, fine, grayish-white hairs.9

Pussy Willow leaves are more oval than other willows.  They grow up to 4 inches long and 1.5 inches across and alternate on the stem.  The edges are irregularly toothed to smooth.  The leaves themselves are medium to dark green and hairless on top.  Underneath, they are hairless, covered with a greenish-white bloom and whitened.  Petioles are up to ¾ inches long and range from smooth to slightly hairy.9  

A few plant facts:  some petioles have stipules where they join the stem.  A stipule is a small structure at the base of a leaf and can be helpful in identifying a plant.  Pussy Willow have largish stipules on both sides of the petiole—1/4 inch long and across.  They are heart-shaped and toothed or lobed.

Salix discolor is a handful.  It’s known to grow tall and wide.  Why choose it for you garden?

S. discolor is a keystone plant and an outstanding one at that. For the Eastern Temperate forests, my area, Salix spp. appears on the Top Keystone Plant Genera list, Top 30 Keystone Plant Genera for Butterfly and Moth Caterpillars and Top 30 Native Host plants for Pollen Specialist Bees.  Keystone plants play an essentially role in their Ecoregions sustaining generalist and specialist pollinators.4

The Xerces Society for Invertebrate Conservation designates Salix discolor as of Special Value to Native Bees, Special Value to Bumble Bees and Special Value to Honey Bees.  While this Willow can become large, it is possible to contain it to a smaller site.  Other native Willows are trees which become much taller and aren’t suited to compact areas.6

A note to readers:  Usually I use all my own photos for my blogs.  Sadly, I don’t have all the images I want for this month.  I’ll be including pictures of pollinators and other insects on other plants and some stock photos.  Thank you for your patience!

Insects are abundant on the Pussy Willow.  Many pollinators feed on the nectar and pollen.  Bee guests include honeybees, bumblebees, little carpenter bees (Ceratina spp.), cuckoo bees (Nomada spp.), mason bees (Osmia spp.), Halictid bees (including green metallic bees) and Andrenid bees (Andrena spp).

Several Andrenid bees are specialists of willows.  Specialists (aka oligoleges) collect pollen from only one genus or species or only a few genera or species.  These Andrenid bees include:  Andrena (Parandrena) andrenoides, Andrena (Thysandrena) bisalicis, Andrena (Tylandrena) erythrogaster, Andrena (Andrena) frigida, Andrena (Micrandrena) illinoiensis, Andrena (Andrena) macoupinensis, Andrena (Trachandrena) mariae, Andrena (Parandrena) nida, Andrena (Micrandrena) nigrae, Andrena (Micrandrena) salictaria, Andrena (Parandrena) wellesleyana.7,9

In addition to these oligoleges, generalists also collect resources from Salix discolor.  Honeybees and bumblebees are among them.

Small bees gather pollen and nectar from Pussy Willows including little carpenter bees (Ceratina spp.), mason bees (Osmia spp.) and Halictid bees (including green metallic sweat bees).

Ichneumonid wasps harvest pollen and nectar from  S. discolor.  These parasitoid wasps prey on immature stages of many insects and spiders.  They help control populations in natural and semi-natural systems.2

Willows are larval hosts for 289 different species of butterflies, skippers and moths.  Examples include many butterflies (i.e., Nymphalis spp. and Polygonia spp. ),  hairstreak butterflies (Satyrium spp.), Viceroy butterflies (Limenitis archippus) and other brush-footed butterflies (Nymphalidae).4,9

The Viceroy has a special relationship with willows.  Its larvae feed at night on the catkins and then the leaves after flowering.  Unlike other butterflies, adults don’t visit flowers.  They drink from tree sap, rotting fruit, honeydew-an excretion from aphids, animal droppings, and mud puddles.8

Large leaf being eaten by viceroy butterfly caterpillar

Honeydew is an excretion from sap-eating aphids.  These aphids concentrate the sap they drink to harvest the protein.  They excrete the excess liquid and sugars as honeydew.  Willows host 22 species of aphids providing an excellent place for Viceroys to hunt for food.3,8

Viceroy Butterfly feeding on nectar from a wildflower.

Moth larvae also consume Salix spp. including tiger moths (Arctiidae), Geometer moths, leaf blotch miner moths (Gracillariidae), slug caterpillar moths (Limacodidae), Lyonet moths, owlet moths (Noctuidae), prominent moths (Notodontidae), giant silk moths (Saturniidae), and Sphinx moths (Sphingidae).9

In addition, hordes of other kinds of insects use willows in various ways.  Among these are flies, beetles, borers, weevils, gall flies, various true bugs, thrips, sawflies, and 22 different kinds of aphids.  You can see a full list in the Insect Table from Illinois Wildflowers (https://www.illinoiswildflowers.info/trees/tables/table65.html).3  

OK, this doesn’t sound like great news.  But, because of all these insects, birds gather many resources from willows.  Wood Duck, Northern Pintail, Mallard, Common Redpoll, Evening Grosbeak, Pine Grosbeak, American Goldfinch, Common Grackle, and Ruffed Grouse all visit willows.  (Bird Table, https://www.illinoiswildflowers.info/trees/tables/table66.html)1

Even Salix discolor’s rapid growth is good news.  A variety of animals use or consume parts of the willow.  Prairie Voles, Meadow Voles, Fox Squirrels and Black Bears eat leaves, buds and/or catkins.  Cottontail Rabbits and Muskrats feed on the bark.  Beavers eat bark and wood and use the branches for dams and lodges.    Snapping Turtles and Wood Turtles forage on fallen leaves.9

There’s so much life around the Pussy Willow!  From the very beginning of Spring through the year, this shrub nurtures insects and animals.  What a grand addition to any garden!

I hope you enjoyed this blog!  Please send me your stories and questions. I’d love to hear from you!

Happy Gardening!

Mary

Bibliography:

  1. “Bird Table (Salix Spp.).” Accessed April 30, 2025. https://www.illinoiswildflowers.info/trees/tables/table66.html.
  2. Missouri Department of Conservation. “Ichneumon Wasps.” Accessed April 30, 2025. https://mdc.mo.gov/discover-nature/field-guide/ichneumon-wasps.
  3. “Insect Table (Salix Spp.).” Accessed April 30, 2025. https://www.illinoiswildflowers.info/trees/tables/table65.html.
  4. National Wildlife Federation. “Keystone Native Plants, Eastern Temperate Forests-Ecoregion 8.  Accessed April 29, 2025.  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
  5. “Salix Discolor – Plant Finder.” Accessed April 28, 2025. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c808.
  6. “Salix Discolor (Pussy Willow) | Native Plants of North America.” Accessed April 28, 2025. https://www.wildflower.org/plants/result.php?id_plant=sadi.
  7. “Salix Discolor (Pussy Willow) | North Carolina Extension Gardener Plant Toolbox.” Accessed April 28, 2025. https://plants.ces.ncsu.edu/plants/salix-discolor/.
  8. Missouri Department of Conservation. “Viceroy,” January 31, 2024. https://mdc.mo.gov/discover-nature/field-guide/viceroy.
  9. “Pussy Willow (Salix Discolor).” Accessed April 28, 2025. https://www.illinoiswildflowers.info/trees/plants/pussy_willow.htm.
Categories
native plants Pollinator gardening

A Fabulous, Fuzzy Flower

Big, bold and filled with butterflies, Sweet Joe-Pye Weed (Eutrochium purpureum) stands out in any garden.  Large mauve-purple flowers feed masses of pollinators.  Not only do butterflies, moths and skippers nectar at the blooms but various caterpillars feed on it.10

Eutrochium purpureum grow in zones four to nine.  It usually ranges from three to seven feet tall.  In a drier location, it can flower at only one foot high and, in an ideal spot, can reach eight to ten feet.2,3,10  

It prefers partial shade to full sun and moist to medium, even moisture conditions.  Rich, loamy soil is ideal.  Eutrochium purpureum spreads by seeds and runners.  

In nature, it’s found in open woodlands, partially shaded seeps, savannas, partially shaded riverbanks and streambanks, thickets, in open woodlands, wet meadows, wooded slopes and low moist ground.2,3,8,10

Given these natural habitats, Sweet Joe-Pye weed easily adapts to wildflower gardens, naturalized landscapes and perennial borders.  Its moisture tolerance means  Eutrochium purpureum enjoys the edges of rain or water gardens.  Recently, Sweet Joe-Pye Weed began self-seeding near my rain gardens.  Finally, it suits both formal and informal settings.

Sweet Joe-Pye Weed will react to less-than-ideal conditions.  In full shade, it becomes leggy and may  fall over.  If it dries out, its leaves turn yellowish green.  

In my garden, it grows tallest in a rainy year.  In partial shade, the plants thrive even without extra water.  In full sun, the plants are more likely to need staking possibly from too little water. 1,2,3,10    

If a shorter plant is preferred, Sweet Joe-Pye Weed can be cut back to approximately two feet in late spring or early summer.  These plants usually bloom around the same time as those that haven’t been cut.  The flowers are a generally a little smaller than usual.1

Don’t give up on this one in the Spring!  It tends to sleep late and the stems develop randomly.  But it has been a very reliable grower in my garden—returning with full and abundant growth each year.

Chicago Botanic Garden grew a variety of Eutrochium spp. and related plants in an evaluative study between 2001 and 2013.  They trialed each genus between four and six years.  Eutrochium purpureum performed well each year with flowers up to twelve inches across.  It suffered from powdery mildew one year but not in others.1

Sweet Joe-Pye Weed has a straight, unbranched, light green stem giving the plant an outstanding erect habit.  The leaf nodes are enlarged and naturally purple.  Some plants have more purple on the stem than others. 2,3,10    

Shallow, fibrous roots support the plant.  Sweet Joe-Pye weed spreads as a clump as well as self-seeding.  If it grows in an unwanted place, the plants are easy to pull.

Eutrochium purpureum’s leaves form an attractive whorl around its stem.  Growing in groups of three to five, the medium green, the matte leaves are ovate to lanceolate with lightly serrated edges.  The lower surface is pale green and may be slightly hairy.  Some ecotypes have vanilla-scented foliage.10

In mid-summer to early fall, Sweet Joe-Pye Weed’s magnificent flowers grace the garden.  The main bloom sits  at the top of the stem.  On established plants, side blossoms form below this head adding to the show. 

Each compound head can measure up to 12 to 18 inches across and are made up of one or more panicles.  In my Southern Michigan garden,  Eutrochium purpureum’s flowerheads range from five inches to twelve inches across.  They are most often between five and eight inches.

Blooms range from whitish pink to purplish pink.  I find the more sun, the deeper the flower color.  Plants growing in deep shade have almost white flowers.  Flowers carry a vanilla scent.

These superb blooms have five to eight disk florets per panicle and no ray florets.  The overall flowerhead is slightly dome shaped. Each floret has a series of overlapping pink, oblong bracts.  As they open, a divided white style is strongly exerted (extended past the floret) giving the bloom a fuzzy look. 2,3,8,10  

Numerous pollinators forage on the compound flowerheads of Sweet Joe-Pye Weed.  Most seek out nectar.  Eutrochium purpureum secretes its nectar at the base of the style.  Each tiny, blooming floret offers a supply.2,3,8,10  

The Xerces Society for Invertebrate Conservation declared Eutrochium purpureum of Special Value to Native Bees.2  Visiting bees include Bombus spp. (bumblebees), Melissodes spp. (miner bees), Coelioxys (cuckoo bees), Agapostemon (metallic green sweat bees) and Megachile spp. (leaf-cutting bees).    In my garden, I’ve also seen other sweat bees like Halictus spp., honey bees (Apis app.) and large and small carpenter bees, Xylocopa spp. and Ceratina spp.

Most of these bees collect nectar.  But Bombus spp. (bumblebees) and Melissodes spp. (miner bees) also gather pollen.8,10

Butterflies, moth, and skippers seek out Sweet Joe-Pye Weed in the mid-summer to early fall.  Celastrina(Azure Butterflies), Epargyreus clarus (Silver Spotted Skipper), Limenitis arthemis arthemis (White Admiral Butterflies), Nymphalis urticae (Milbert’s Tortoiseshell Butterflies), Papilio glaucus (Eastern Tiger Swallowtail Butterflies), and Danaus plexippus (Monarch Butterflies) sip the nectar from the fluffy, pink flowerheads.

Eutrochium purpureum is also a larval host supporting several moth caterpillars.  These eat its leaves and other parts.  Emmelina monodactyla (Common Plume Moth), Perigea xanthioides (Red Groundling), Phragmatobia fuliginosa (Ruby Tiger Moth), and Eupithecia miserulata (Common Pug) all feed on Sweet Joe-Pye Weed’s leaves. Carmenta bassiformis (Eupatorium Borer Moth) consumes the roots.  Schinia trifasciata (Three-Lined Flower Moth) relies on its flowers. 4,5,6,8,9,10

Beneficial insects are not particularly attracted to Eutrochium purpureum.  Flies, thread-waisted and sand wasps occasionally visit. Instead, these short-tongued beneficials flock to another Eutrochium—the white blooming Boneset (Eupatorium perfoliatum).8 But that’s the subject for another blog!

I hope you’ve enjoyed hearing about Sweet Joe-Pye weed—a stunning, versatile and useful plant.  Eutrochium purpureum is easily available at most native plant nurseries.  Next year those big, fuzzy flowers could be blooming in your garden!

If you’ve enjoyed this blog and would like to leave a comment or share a story, please contact me in the box below!

Warm Regards,

Mary

References:

  1. Hawke, Richard. “A Comparative Study of Joe-Pye Weeds (Eutrochium Spp.) and Their Relatives,” n.d.
  2. “Eutrochium Purpureum (Gravel Weed, Indian Sage, Joe-Pye Weed, Marsh Milkweed, Motherwort, Pride of the Meadow, Purple Joe-Pye Weed, Sweet Joepyeweed) | North Carolina Extension Gardener Plant Toolbox.” Accessed October 20, 2024. https://plants.ces.ncsu.edu/plants/eutrochium-purpureum/.
  3. “Eutrochium Purpureum (Purple Joepyeweed) | Native Plants of North America.” Accessed October 20, 2024. https://www.wildflower.org/plants/result.php?id_plant=eupu21.
  4. “Minnesota Seasons – Common Eupithecia.” Accessed October 30, 2024. http://www.minnesotaseasons.com/Insects/common_eupithecia.html.
  5. Missouri Department of Conservation. “Plume Moths.” Accessed October 30, 2024. https://mdc.mo.gov/discover-nature/field-guide/plume-moths.
  6. Missouri Department of Conservation. “Three-Lined Flower Moth.” Accessed October 30, 2024. https://mdc.mo.gov/discover-nature/field-guide/three-lined-flower-moth.
  7. “Perigea Xanthioides.” In Wikipedia, January 8, 2023. https://en.wikipedia.org/w/index.php?title=Perigea_xanthioides&oldid=1132346411
  8. Holm, Heather. Pollinators of Native Plants:  Attract, Observe and Identify Pollinators and Beneficial Insects with Native Plants. Minnesota: Pollination Press LLC, 2014.
  9. “Species Phragmatobia Fuliginosa – Ruby Tiger Moth – Hodges#8156.” Accessed October 30, 2024. https://bugguide.net/node/view/41933.
  10. “Sweet Joe-Pye Weed (Eutrochium Purpureum).” Accessed October 20, 2024. https://www.illinoiswildflowers.info/savanna/plants/sw_joepye.htm.
Categories
native plants Pollinator gardening

A Summer Cornucopia

Part 2

And we’re back for Part II of The Summer Cornucopia!  Today the focus is on insects and how they use Common Milkweed.  If you missed Part I and are interested in the plant and pollination, here’s a link: https://wordpress.com/post/wildthingsinthe.garden/1831.

Asclepias syriaca draws an abundance of insects.  The sap, leaves and flowers are all used for food while blooms provide nectar to many insects.  Common Milkweed supports different life stages of flies, wasps, bees, butterflies, moths, skippers, plant bugs and beneficial insects.  Even hummingbirds try to sip nectar although they can’t reach it.1,7  

The most famous visitor to Common Milkweed is the Monarch butterfly (Danaus plexippus).  Monarchs can only use milkweeds (Asclepias) to feed their caterpillars. Growing milkweed supports the generations of Monarchs that hatch over the summer months.  When the last summer generation is born and transforms into an adult, they’ll drink nectar from milkweed and other flowers for food and fuel for their migration.8  

Growing native milkweeds helps preserve the existing Monarch population.  If you’re interested in helping Monarchs, Monarch Watch has excellent information on creating Monarch Waystations at https://www.monarchwatch.org/waystations/ .  Here are the highlights of the plan!8

How big does a waystation have to be?  Any size will help the Monarchs (and other pollinators!).  If possible, a 100 square foot waystation is highly effective.  The area doesn’t have to be all in one spot.  There can be several plantings throughout a property.

Sun is important for Monarchs.  Like other insects, they need heat and sunlight to warm themselves for flying and daily activities.  An area with six or more hours of sunlight is required.  Coincidentally, most milkweeds thrive under those conditions.

Milkweed also grow well in well-drained soil.  Place Monarch Waystations in low clay areas with fast draining soils.

Place plants close together (although not closer than recommended).  Monarchs and their caterpillars need shelter and protection from predators and the weather.

What about milkweed?  At least ten plants are recommended preferably with two or more types of milkweeds.  This planting scheme gives an extended season of bloom and allows the Monarchs longer access to the milkweed plants and nectar.  One type of milkweed is okay if more than ten plants are included.

Establish continuous supply of nectar plants.  Use annual, biennial and perennial plants.  Native plants are a great choice.  These plants also benefit the other pollinators.

Finally, create a management plan.  How will the waystation be maintained?  The plan contains basic garden maintenance:  mulching, fertilizing, removing invasive plants.  Additionally, it includes Monarch specific items:  eliminate insecticides, add more features like a water source or puddling spot.

Again, for more information on Monarch Waystations and other resources, including free milkweed programs, go to https://www.monarchwatch.org/waystations/

In addition to Monarchs, swallowtails (Papilio), fritillaries (Speyeria), viceroy butterflies (Limenitis), sulfurs (Pieris), and other butterflies also visit Asclepias syriaca.  Skippers use Asclepias syriaca for nectar including Ancyloxipha.1,7  

Common Milkweed is a larval host for the striking Milkweed Tussock Moth (Euchaetes egle) caterpillar, the Unexpected Cycnla (Cycnia inopinates) and the Delicate Cycnia (Cycnia tenera).  All are part of the group Artiinae or Tiger Moths.1  

The Delicate Cycnia (Cycnia tenera) lacks the usual aposematic coloration  It has a soft tan larva and a charming white adult with just a touch of orange on the head and wing edges.  Instead, it emits aposematic ultrasound calls when caught!  Bats release their prey when they hear the calls.  During the day, their color variation seems to keep birds away.1,9

Both long-tongued and short-tongued bees visit Common Milkweed for nectar.  These include honeybees (Apis),

Bumble Bees (Bombus),

leaf-cutter bees (Megachile),

cuckoo bees (Coelioxys), small carpenter bees (Ceratina)

and sweat bees (Halictus and Lasioglossum).1,7,10

Many wasps enjoy nectaring at Milkweed flowers especially Sphex, Tachytes, Polistes,  Myzinum, and ichneumon wasps.  Sphex ichneumoneus is a known pollinator of Common Milkweed.1,7

Numerous beneficial insects visit Asclepias syriaca including the delicate and diverse ichneumon wasps.  The adult wasps use milkweeds’ nectar for fuel while searching for insect prey.  They’re considered parasitoids and the females lay eggs inside grubs and caterpillars.  

Young of boll weevils, tomato hornworms and wood borers are all food for ichneumon wasps.  In addition to garden pests, adults hunt large insects such as spiders and butterflies.  

In general, ichneumon wasps help reduce the number of insects that reach reproductive age.  Many of these prey insects damage trees.  In this way, the wasps help keep trees healthy.11

Bembix americana, a predatory sand wasp, also gathers nectar from Common Milkweed.  B. americanafeeds their young true flies (Diptera).  Diptera include house flies, gnats and mosquitos.  

As populations of flies increase, B. americanas numbers rise.  A single larvae can eat two dozen flies.  B. americana uses a different strategy for provisioning its young.  Other wasps paralyze their prey and stock each cell with the required (living but paralyzed) insects.  This sand wasp kills the flies and adds more food as needed.12

Asclepias syriaca hosts predatory stink bug larvae.  Stink bugs have a terrible reputation especially since the arrival of  the invasive Brown Marmorated Stink Bug.  But predatory stink bugs are a whole different category.  These are beneficial insects that hunt insect prey.  

Above, is a photo of a Spined Soldier Bug larvae on milkweed.  There are five larval stages (instars) and all eat insects.  Their preferred foods include Mexican bean beetle, Colorado potato beetle, and imported cabbageworm.  

Look for the adult Spined Soldier Bug on plants where prey may be located.  These plants include the melons/squash/cucumber (cucurbit), broccoli, cauliflower, kale, etc. (cruciferous) and tomatoes, peppers, eggplant (solanaceous) crops.  

If you’re looking for eggs, they’re an incredible metallic bronze color with a row of spines like a crown.  Just hatched larvae, cluster around the eggs eating necessary bacteria.  Spined Soldier Bug can be purchased commercially.13

In addition to all these, Asclepius syriaca hosts many beetles and bugs,

grasshoppers,

and leafhoppers

Finally, flies, including beneficial ones, nectar on Asclepius syriaca.

I hope you’ve enjoyed this exploration of the insects found on Common Milkweed.  Pollinators and beneficials all enjoy Asclepias.  It’s always worth stopping to see who’s home in the milkweed patch with or without flowers!

Happy Gardening, 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.
  8. No author, n.d., Monarch Waystation Program, https://monarchwatch.org/waystations/
  9. Geere, Duncan, 2010. August.19, Tiger Moths Scare Bats with Ultrasonic Clicks, Wired, https://www.wired.com/2010/08/moth-jamming/
  10. Holm, Heather, 2017, Bees:  An Identification and Native Plant Forage Guide, Pollination Press LLC
  11. No author, n.d., Ichneumon Wasps, Discover Nature>Field Guide:  Missouri Department of Conservation, https://mdc.mo.gov/discover-nature/field-guide/ichneumon-wasps
  12. No author, n.d., Sand Wasps, Discover Nature>Field Guide:  Missouri Department of Conservation, https://mdc.mo.gov/discover-nature/field-guide/sand-wasps
  13. Berish, Chelsea, n.d., Spined Soldier Bug in Kentucky, ENTFACT-325: SPINED SOLDIER BUG IN KENTUCKY, University of Kentucky Department of Entomology, Martin Gatton College of Agriculture, Food and Environment
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

Grist for the Bees

Purple Wheat in the garden?  Indeed, that’s what Agastache means ‘agan’ much, ‘stachys’ ear of grain, from the Greek.  Its flowers look like heads of wheat or rye and range from pale lavender to purple.  ‘Foeniculum’, the second part of the name, means fragrant for the scented leaves.  Agastache foeniculum (Fragrant or Anise Hyssop) is part of the mint family.  Like Pycnanthemum virginianum (https://wildthingsinthe.garden/2023/05/31/white-goes-with-everything/), also mints, it attracts an enormous variety of bees.  Fragrant Hyssop also supports numerous butterflies and skippers.

Anise Hyssop grows two to four feet tall and spreads eighteen inches to two feet.  It has an upright, clump-forming habit.  Anise Hyssop sports dark green, ovate to broadly lanceolate leaves up to four inches long.  Almost heart shaped, the leaves are one to three inches at the base and whitish underneath.  They sit opposite each other on the classic square stem of mint plants.  The foliage also gives off a strong anise or licorice-like scent that gives the plant its common and Latin name.

Agastache foeniculum can begin blooming in June and continues through August.  In zone 5, where I am, it doesn’t start until July.  Blooms appear as three- to six-inch-long flower spikes at the end of plant stalks.  The eye-catching blossoms range from pale lavender to true purple in color.  Tiny flowers make up each large spike.  They’re laid out in tightly packed rows although there can be gaps (think of an ear of corn).  This arrangement is called verticillasters or false whorls.  Each of the small flowers is tubular, 2-lipped and a 1/3’’ inch long.  Unlike the leaves, the blooms have no scent. 

Fragrant Hyssop plant grows best in full sun with dry to moderately moist soil.  Soil moisture is not a problem if the drainage is good.   Anise Hyssop is drought tolerant, more so after it is established.  It spreads by rhizomes and self-seeding especially under good conditions.  I have not found that this plant spreads obnoxiously.  I have far fewer Anise Hyssop seedlings than Monarda fistulosa seedlings.  Fragrant Hyssop may have problems with crown rot with soggy soil. Other issues include rust and powdery mildew.

Outside of cultivation, Agastache foeniculum grows in prairies, dry upland forests, plains, fields, roadsides, and other dry, open, semi-shaded areas.  In the past, it served as honeybee forage in Canada and parts of the Upper Midwest.  It works well in borders, wildflower gardens, herb gardens, butterfly gardens and meadows.

Agastache foeniculum and similar species inspire plant breeders around the world.  Too many nativars exist to explore them all, but I thought we could look at three very different plants.  Each of these was modified in a different way.

Agastache ‘Blue Fortune’ is a very popular hybrid created by crossing Agastache foeniculum with its East Asian relative, Agastache rugosa.  This compact plant has longer flower spikes than the species.  It blooms for an extended time because it’s bred to be sterile.  ‘Blue Fortune’ is widely reported to be a pollinator magnet.

Agastache ‘Golden Jubilee’ is an older hybrid with yellow-green foliage that’s pure yellow in the Spring. The flowers are identical to the species.  ‘Golden Jubilee’ received the All-American Selection Award in 2003 and is still being sold.  It will self-seed with a mix of species and golden seedlings.  There are mixed reports on how pollinators respond to ‘Golden Jubilee’.  Some sources say bees don’t seem to ‘see’ it and others say pollinators love it.

Agastache ‘Red Fortune’ has red to pink flowers.  The leaves are like the species.  Pollinators don’t like this plant as much as Agastache foeniculum.

These three plants give a nice snapshot of how natives are altered and some pollinator responses.  One idea is that nativars with flowers most like the species’ flowers would be most acceptable.1  Positive reports about ‘Blue Fortune’ and ‘Golden Jubilee seem to support this idea.2

In addition, red is a special case.  Bees see in the ultraviolet spectrum—from approximately 300 to 650 nm.  They can’t see red although they can see reddish tones like orange.  When native plants are hybridized for red flowers, bees often have trouble finding them.1,3

But wait!  There’s an exception.  Red flowers can have ultraviolet “nectar guides”  which the bees see perfectly well.  Plants use these guides to “direct” the pollinators to the nectar reward and encourage pollination.3  

It’s hard to say if a red native hybrid will still attract and support bee pollinators.  If they retain their ultraviolet nectar guides, then the bees should see them.  However, I’ve seen more than one report showing little to no bee activity on the red and pink hybrids.1,2

Anise Hyssop serves a multitude of pollinators providing nectar and pollen.  Like Monarda (https://wildthingsinthe.garden/2023/07/31/the-gardens-super-station/), Fragrant Hyssop has been identified by pollination ecologists as attracting large numbers of native bees.  The Xerces Society for Invertebrate Conservation also designated Fragrant Hyssop of Special Value to Bumble bees and Honeybees.  Butterflies and skippers use it for a nectar source.

Pollination in Fragrant Hyssop hinges on both the individual flowers’ structure and the different bees’ anatomies.  The nectar is secreted by a disc at the base of the flower.  Pollen-carrying anthers are located on the top lip of each flower.  When bees root for nectar, pollen rubs off onto their heads or thorax.  As they move to a bloom with a receptive stigma, female part, the pollen transfers and fertilization occurs.

The many native bees that visit Hyssop range from large to tiny.  Bumble bees are the largest.  I’ve seen Common Eastern Bumble bee (Bombus impatiens), Brown-Belted Bumble bee, (Bombus griseocollis), Two-Spotted Bumble bee (Bombus bimaculatus), and Golden Northern Bumble Bee (Bombus fervidus) on my Fragrant Hyssop. They use both nectar and pollen for their larva.  

Large Leaf-Cutter bees use Anise Hyssop’s nectar. In the process, they are efficient pollinators. In contrast to other bees, pollen accumulates on the Leaf-Cutter bees’ abdominal scopae (specialized pollen collecting hairs).  It is transferred to the stigmas from there.


Digger bees (Melissodes) and smaller Leaf-Cutter bees (Megachile) are mid-sized bees.  They also collect both pollen and nectar from Anise Hyssop.

The Halictid bees (Lasioglossom), small Resin bees (Heriades) and Masked bees (Hylaeus) are small bees that gather resources from Fragrant Hyssop.  Dufourea monardae is included in this group.  D. monardae is a specialist or oligolectic bee that visits Monarda fistulosa and Agastache foeniculum.  These small bees can collect pollen from the anthers extending from the flowers. When harvesting nectar, they climb the style to reach the base of the flower.  (The style is the stalk connecting the stigma and the ovary.)

Fragrant Hyssop provides an excellent late season nectar source for butterflies, skippers and moths including Silver Spotted Skipper Butterflies (Epargyreus clarus), Peck’s Skipper Butterflies (Polites peckius) and the Great Spangled Fritillary Butterfly (Speyeria cybele).  They reach their proboscis into each tiny bloom to find the nectar.  Hyssop also works well in Monarch Way Stations providing food after most milkweed has stopped blooming.  

I hope you enjoyed this exploration of Anise Hyssop and its wonderful visitors!  I’d love to hear your thought about this blog or stories about your own experiences in the garden.  Please leave me comment and let me know your thoughts!

References:

  1. Eierman, Kim,11 April 2014,  “Ecobeneficial Interview:  Annie White on Native Plant Cultivars, Native Plants and Pollinators”, Youtube, https://www.youtube.com/watch?v=HTmuDcEzTOw
  2. Caldwell, Cathy, (2021, August-Vol.7, No.8) Anise hyssop, Piedmont Master Gardeners, https://piedmontmastergardeners.org/article/anise-hyssop/
  3. Riddle, Sharla, (2016, May, 20) How Bees See And Why It Matters, Bee Culture:  The Magazine of American Beekeeping, https://www.beeculture.com/bees-see-matters/