Tag: Ceratina

Categories
native plants Pollinator gardening

A Giant for Your Garden

Silphium terebinthaceum (Prairie Dock)

Rising high above tall grasses, Prairie Dock’s light-yellow blooms open in the sun.  Silphium terebinthinaceum or Prairie Dock is one of the Silphiums, often called the giants of the prairie.  It’s tall flower stalks live up to the name rising 8 to 10 feet.  Yet the base stays a manageable 1 to 3 feet across making it reasonable for the home garden.8,9  

One of the Keystone plants for Ecoregion 8-Eastern Temperate Forests, it supports specialist bees, native bees, bumbles bees and other long-tongued bees and bee flies.  Hummingbirds visit the flowers and finches eat the seeds.  Parasitic and Hyperparasitic wasps use Prairie Dock for nesting and reproduction.4,8,9

Silphium terebinthinaceum grows in zones 4 to 8.  The flower stalks reach up to 10 feet and the plant spreads from 1 to 3 feet.  This plant thrives in full sun but tolerates part shade.  Deep, loamy soil is ideal.  Rocky or gravelly soil, clay, limestone or dolomite rocky soil are all acceptable.8,9

In a natural setting, Prairie Dock lives in moist to dry black soil prairies, fens, shrub prairies, gravel prairies, hill prairies, tops of bluffs, seeps, upland or rocky prairies, savannas, old fields, prairie remnants, along roads and railways, glades, openings of dry upland forests, woodland borders, and, rarely, banks of streams.8,10

Prairie Dock’s leaves are remarkable!  Growing up to 18 inches long and 12 inches wide, they emerge in a vase-shaped rosette.  In full sun, the leaves orient from North to South.  This direction maximizes photosynthesis and reduces transpiration.6,8,9

The foliage itself is heart shaped or cordate.  It has a thick, sand papery texture.  The upper surface of young leaves is mostly hairless and shiny but older leaves become matte and rough.8

Its flowers bloom from summer into fall-opening from multiple buds.  These compound flowerheads have 15 to 30 ray florets and many disc florets.  They are 2 to 3 inches across.6,8

Here’s a fun botanical fact!  The flowers of Silphium and Helianthus (Wild Sunflower) are astonishingly similar but there is a key difference.  The centers (disc flowers) of Helianthus are the female or pistillate florets.  As seen in commercial sunflowers, these become seeds.  In the Silphium flowers, only the ray flowers (those attached to petals) are female.  Seeds only form around the edge of Silphium’s compound flower head.6

Silphium terebinthinaceum’s blooms on long, smooth stalks.  These rise from 3 to 10 feet and branch at the top to hold several blossoms.  The flower stalks don’t usually need support but often lean.  In fact, the only place I’ve seen them stand straight is on a median strip.8,9

The Prairie Dock plant is slow to establish taking 2 to 3 years flower in cultivation. In the wild, it can take considerably longer.  Once established it’s almost impossible to kill.  The tap root can grow to 12 feet and the plant resists drought, fire and herbivore predation.8

The deer ate my Prairie Dock to the ground for several years.  I assumed it was dead.  Then the township started a controlled hunt.  The deer population went down and my S. terebinthinaceum grew back.  Now it’s fully grown and blooms every year.

Prairie Dock attracts long-tongued and short-tongued insects.  It’s a Region 8 Keystone plant supporting pollen specialist bees.  In addition, The Xerces Society for Invertebrate Conservation has designated it of Special Value to Native Bees, of Special Value to Bumble Bees and declared it Provides Nesting Materials/Structure for Native Bees.4,8,10

Honeybees,

Bumblebees,

and Miner bees are among the long-tongued visitors.  

Short-tongued guests include Halictid bees, resin bees (Heriades spp. and Megachile spp.), small carpenter bees (Ceratina spp.),

beetles and bee flies.  The Ruby-Throated Hummingbird also uses S. terebinthinaceum for nectar and, possibly, small insects.  Small mammals, Goldfinches and other Finches eat the seeds.8

Silphium terebinthinaceum attracts resin bees.  Silphium is a very old name for a resinous plant and this whole group are commonly called rosinweeds.  The specific epithet ‘terebinthinaceum’  means ‘with

turpentine’ referring to the scent of the resinous sap.7

Heriades use resin from Prairie Dock to build their nests.  These bees use existing cavities for nests.  These cavities include beetle burrows, cavities in rocks, hollow stems and abandoned mud dauber nests.  Heriadeswill nest in bee hotels and nest boxes.3

In addition to nectar and pollen, Prairie Dock provides a home for a gall wasp and its parasite. The gall wasp, Antistrophus rufus,  nests in the stem where it forms small galls.  These insects each plant matter.  They’re considered a valuable prey animal for other insects, small insect-eating birds and woodpeckers.  A. rufus also indicates a healthy, diverse ecosystem.8

Eurytoma lutea parasitizes A. rufus.  When a parasite preys on another parasite, it’s called a hyperparasite. E. lutea feeds on a variety of gall-forming wasps which can damage plants.  This wasp is a beneficial insect since it helps control populations of the gall-forming wasps.8

The Tumbling Flower Beetle (Mordellistena aethiops) lives in and on Prairie Dock.  The larvae stay inside the stem, and most are stem-borers.  They, also, eat other plant parts, decaying wood and fungus.1,5  

The adults are charming, shiny, black beetles.  They eat nectar and pollen.  While they move around the flower head, the Tumbling Flower Beetles contribute to pollination.  

These beetles are also known for…tumbling!  Just like their name, when startled, they look like their rolling rapidly off the flower.  The Tumbling Flower Beetle has a complex way of moving involving a series of short hops.  They alternate legs, leaping every 80 ms.  The goal is to evade a predator and get into a good flight position.  It also startles the person reaching for it!1,5

Hope you enjoyed our exploration of Prairie Dock—the garden-size Silphium!  This plant gives a home to a multitude of pollinators and other insects.  It’s also a stunning plant in the garden!

Happy Gardening,

Mary

Bibliography:

  1. Farley, Jeanine. 2025. “Getting a Kick out of the Tumbling Flower Beetle Means You’ve Caused the Critter to Panic and Flee.” Cambridge Day, July 19. https://www.cambridgeday.com/2025/07/19/getting-a-kick-out-of-the-tumbling-flower-beetle-means-youve-caused-the-critter-to-panic-and-flee/
  2. “Flower-Visiting Birds and Insects of Prairie Dock”, n.d. Accessed September 3, 2025, https://www.illinoiswildflowers.info/flower_insects/plants/prairie_dock.htm
  3. Holm, Heather. 2017. Bees:  An Identification and Native Plant Forage Guide. Pollination Press LLC.
  4. “Keystone Native Plants:  Eastern Temperate Forests-Ecoregion 8” n.d. Accessed September 3, 2025, https://www.nwf.org/-/media/Documents/PDFs/Garden-for-Wildlife/Keystone-Plants/NWF-GFW-keystone-plant-list-ecoregion-8-eastern-temperate-forests.pdf
  5. “Mordellidae – an Overview | ScienceDirect Topics.” n.d. Accessed September 3, 2025. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/mordellidae
  6. Missouri Department of Conservation. n.d. “Prairie Dock (Prairie Rosinweed).” Accessed September 3, 2025. https://mdc.mo.gov/discover-nature/field-guide/prairie-dock-prairie-rosinweed.
  7. Missouri Department of Conservation. n.d. “Silphium.” Accessed September 3, 2025. https://mdc.mo.gov/magazines/conservationist/2000-08/silphium.
  8. “Prairie Dock (Silphium Terebinthinaceum).” n.d. Accessed September 3, 2025. https://www.illinoiswildflowers.info/prairie/plantx/pr_dockx.htm.
  9. “Silphium Terebinthinaceum – Plant Finder.” n.d. Accessed September 3, 2025. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=f590.
  10. “Silphium Terebinthinaceum (Prairie Rosinweed) | Native Plants of North America.” n.d. Accessed September 3, 2025. https://www.wildflower.org/plants/result.php?id_plant=site.
Categories
native plants Pollinator gardening

Moons in the Wetlands

The glowing spheres of Buttonbush blooms shine in its dark foliage.  The 2023 North Carolina Wildflower of the Year, Buttonbush (Cephalanthus occidentalis) thrives in difficult wet, low spots, even shallow standing water.  It supports pollinators, beneficial insects and is a larval host.   Cephalanthus occidentalis is also a rare mid-summer blooming shrub.

Buttonbush grows in zones 4-8.  It generally measures between 4 and 8 feet tall and spreads between 4 and 8 feet.  C. occidentalis enjoys full sun to part shade.  It flourishes in medium moisture to wet soils including shallow standing water and areas with occasional flooding.  Humusy soils, clay, loam, sand, shallow rocky soil, limestone soil, sandy loam, medium loam and clay loam all support Buttonbush.2, 3

Buttonbush grows in diverse wet habitats in nature.  These locations include wet open areas, low woods, floodplain forests, vernal pools in wooded areas, wet thickets, shrubby swamps, upland sinkholes, wet depressions in black soil prairies, marshes, bogs, seeps, seasonal wetlands, ponds, pond margins, lakes-often in water up to 3 inches, prairie swales, dry limestone bluffs, ditches, and borders of rivers, and streams.2,4

In addition to flourishing in wet conditions, Buttonbush tolerates various challenges.  It’s moderately deer resistant since its foliage contains a toxin.  This shrub works for erosion control.  Its swollen base stabilizes the plant.  It also survives competition, fire, and heat.4,12

If the species shrub becomes too big, rejuvenation pruning in early spring makes it more manageable.  Rejuvenation pruning is a technique used on multi-stemmed, twiggy shrubs.  The shrub is cut back to between 6 and 12 inches above the ground.  The individual stems are cut ¼ inch above a bud.  Cuts slope down and away from the bud at a 450 angle.   Remove dead wood as close to the ground as possible.  This method also works well Red-Twig Dogwood (Cornus sericea) and Pussy Willows (Salix discolor).7

If the species Cephalanthus occidentalis is still too large or unruly for your space, there is a smaller nativar. Buttonbush Sugar Shack grows to approximately 5 feet by 5 feet at maturity.  Sugar Shack is ball-shaped with compact growth.6

It enjoys the same conditions as the species-full to part sun and moist to wet soils.  The white flowers are similar in size and bloom from early to late summer (beginning to last blossom).  The seeds pods are red, becoming brown over the winter.  The foliage changes to burgundy in the fall.6

Foliage of Cephalanthus occidentalis is medium to dark green.  The leaves sit opposite each other in pairs or, occasionally, in whorls of 3.  They grow up to 6 inches long and 2.5 inches across.2

Each leaf has a smooth margin and an ovate or ovate-oblong shape.  Their upper surface is glossy, and the most common variety is hairless.  A pubescent (covered with soft, short hairs) variety also exists.  The foliage changes to yellow in the autumn.2

The spherical flowers start the show with Buttonbush.  They’re located at the top of branches or emerge from leaf axils.  These flowerheads grow from 1 to 2 inches across and are white or cream colored.2

Within the flowerhead, each floret consists of an approximately 1/3-inch-long corolla. It has 4 lobes at the opening.  There are 4 stamens and 1 undivided, white style.  The style extends beyond the floret opening.2

Buttonbush is self-incompatible and has an unusual way of releasing its pollen.  The stamens emerge first.  They shed pollen while the florets are still closed.  Then the florets open.  While the style elongates, it carries along the pollen and makes it accessible to bees and insects.

Cephalanthus occidentalis blooms for about 1 month.  The flowers are followed by red, round seedheads.  These remain throughout the winter turning brown and giving winter interest.2

Buttonbush feeds numerous creatures.  For the insects, C. occidentalis provides nectar and pollen and is of Special Value to Native Bees, of Special Value to Bumble Bees and Special Value to Honey Bees. XERCES Butterflies, moths and skippers, also, harvest resources from the flowers as well as wasps and flies. It’s also a larval host for many moths including the spectacular Titan Sphinx Moth (Aellops titan).2

Many different bees gather nectar from Cephalanthus occidentalis.  These include  Honeybees (Apis mellifera), bumblebees (Bombus), cuckoo bees (Triepeolus spp.), long-horned bees (Melissodes spp.), leaf-cutting bees (Megachile spp.), green metallic bees (Agapostemon spp.), small carpenter bees (Ceratina spp.), yellow-faced bees (Hylaeus spp.) and large carpenter bees (Xylocopa spp.).2

In the past,  Buttonbush support a large beekeeping industry along the lower Mississippi River floodplain where the shrub thrived.  It’s still known by the common names of Honeybush, Honeybells and Honeyballs.  Honeybees continue to seek out its nectar and pollen.13

Bumble bees frequently visit C. occidentalis when it’s flowering.

Small bees gather resources at Buttonbush, climbing in and out of the florets.  These pollinators include small carpenter bees (Ceratina spp.), green metallic bees (Agapostemon spp.), and yellow-faced bees (Hylaeus spp.).

There are 366 species of small carpenter bees (Ceratina spp.) throughout the world (except Oceania).  27 species live in the United States with 5 in the Eastern US and Canada.8,11  Despite their name, they’re not closely related to the carpenter bee, Xylocopa. 

 Ceratina are stem nesting bees that need pithy centers.  They nest in perennials and woody stems.  The female excavates a long nesting tunnel and uses the stem pith to create cell divisions.  Once the nest is full, the female guards the entrance.  She makes a yellow, strongly citral-scented secretion that is excreted from her mandibles (“jaws”).  The mother smears this on the nest entrance to repel predators.8,11

Ceratina show some unusual and fascinating social behaviors.  Unlike other bees, small carpenter bees live a long time, 12 to 16 months.  In temperate climates like the Northeast and Great Lake, this means through the winter.  

These bees care for their young throughout this time.  The mother removes the nest partitions each evening and grooms her young.  This behavior is believed to reduce parasites and remove any developing fungal infections from the nest.  These mother-offspring interactions separate Ceratina from other solitary bees and are considered subsocial.8,11

Various wasps drink nectar from Cephalanthus occidentalis.  Scoliid wasps (Dielis spp.), Carrot or Gasteruption wasps (Gasteruption spp.), and  Thynnid Flower wasps (Myzinum spp.) are solitary, parasitic or parasitoid wasps which visit Buttonbush.  In addition, the solitary wasps, Mason wasps (Monobia spp.), Cuckoo wasps (Parnopes spp.), (Pseudodynerus spp.), and Thread-Waisted wasp (Sphex spp). also use C. occidentalis.   Finally, the very social yellow jacket, (Vespula spp.) gathers nectar from this shrub.9

The Great Golden Sand Digger Wasp (Sphex ichneumoneus) is a beautiful, beneficial wasp.  This digger wasp hunts cicadas and true crickets to provision its nests.  The female constructs a vertical nest with 2 or 3 side cells for eggs. She lays her egg on the first prey and adds 1 to 5 more.  The number of nests per year vary depending on the length of growing season.  Like other solitary wasps, the Great Golden Sand Digger Wasp is not aggressive, and, in fact, the male doesn’t have a stinger.9,10

Thick-headed flies and Syrphid flies gather nectar from Buttonbush flowers.2

Buttonbush serves adult butterflies, moths and skippers.2,5,13  They visit its blooms for nectar.

Several moths use this shrub as a larval host including some spectacular ones.  The Titan Sphinx (Aellops titan), the Hydrangea Sphinx (Darapsa versicolor), and the  Royal Walnut Moth (Cithermia regalis) larvae all feed off the Cephalanthus occidentalis plant.2,5,13

Hope you’ve enjoyed this dive into Cephalanthus occidentalis!  Look for it blooming when you’re near water.  Check for it at the edges of wetlands by roadside ditches. 

Enjoy Summer and Happy Gardening,

Mary

BIBLIOGRAPHY:

  1. “Bird Table (Cephalanthus Occidentalis).” Accessed July 1, 2025. https://www.illinoiswildflowers.info/trees/tables/table283.html.
  2. “Buttonbush (Cephalanthus Occidentalis).” Accessed July 1, 2025. https://www.illinoiswildflowers.info/trees/plants/buttonbush.htm.
  3. “Cephalanthus Occidentalis – Plant Finder.” Accessed July 1, 2025. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=g830.
  4. “Cephalanthus Occidentalis (Buttonbush, Button Bush) | North Carolina Extension Gardener Plant Toolbox.” Accessed July 1, 2025. https://plants.ces.ncsu.edu/plants/cephalanthus-occidentalis/.
  5. “Cephalanthus Occidentalis (Common Buttonbush) | Native Plants of North America.” Accessed July 1, 2025. https://www.wildflower.org/plants/result.php?id_plant=ceoc2.
  6. “Cephalanthus Occidentalis ‘SMCOSS’ SUGAR SHACK – Plant Finder.” Accessed July 1, 2025. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=443503&isprofile=0&.
  7. Fogerty, Elane, New Jersey Agricultural Experiment Station.  Pruning Flowering Shrubs.  Cooperative Extension Fact Sheet FS1221.  December 2013.
  8. Holm, Heather. Bees:  An Identification and Native Plant Forage Guide. Minnetonka, MN: Pollination Press LLC, 2017.
  9. Holm, Heather. Wasps:  Their Biology, Diversity, and Role as Beneficial Insects and Pollinators of Native Plants. Minnesota: Pollination Press LLC, 2021.
  10. Missouri Department of Conservation. “Great Golden Digger Wasp.” Accessed July 1, 2025. https://mdc.mo.gov/discover-nature/field-guide/great-golden-digger-wasp.
  11. Rehan, Sandra M. “Small Carpenter Bees (Ceratina).” In Encyclopedia of Social Insects, edited by Christopher K. Starr, 1–4. Cham: Springer International Publishing, 2020. https://doi.org/10.1007/978-3-319-90306-4_106-1.
  12. Wennerberg, Sarah. USDA NRCS. Plant Guide:  Common Buttonbush, Cephalanthus occidentalis L. Plant Symbol=CEOC2, Last edit:  05 June 2006, https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_ceoc2.pdf
  13. Xerces Society. “Planting for Pollinators: Button Bush.” Accessed July 1, 2025. https://www.xerces.org/blog/planting-for-pollinators-button-bush.