Bountiful Blue Wood Aster

Blue Wood or Heart-leaved Aster (Symphyotrichum cordifolium) began its seasonal bloom in late September, and amazingly, at the end of November it’s still possible to find some blossoms.

Blue Wood Aster (Symphyotrichum cordifolium) with Sweat Bee (Halictus species)

Blue Wood Aster (Symphyotrichum cordifolium) with Sweat Bee (Halictus species)

Like all Aster (Asteraceae) family members, each flower ‘head’ of Blue Wood Aster consists of many tiny flowers that bloom gradually over a period of several weeks, offering nectar and pollen to a variety of flower visitors.  Each Blue Wood Aster flower head has an outer ring of ice blue petal-like ray flowers designed to advertise this feast. Tiny tubular disk flowers form the center of the display; this is where Blue Wood Aster makes its bountiful food available in hope that while dining, visitors will pick up pollen and transfer it to another plant of the same species, enabling pollination to occur.

Blue Wood Aster’s disk flowers are pale yellow when they’re in bud and when they first open. They turn pink or magenta as they age, and when they have been successfully pollinated.  This color change is a signal to pollinators, directing them to the receptive yellow flowers which are not yet pollinated and that will reward them with nectar, and steering them away from blossoms that are already satisfactorily pollinated and will not produce a nectar reward.  This evolutionary adaptation makes the most efficient use of both the plant’s and the potential pollinator’s efforts.

To share in the bounty offered by Blue Wood Aster, I invite you to a virtual time-lapse visit to our garden in central New Jersey.  You can see the last Blue Wood Aster blossoms for this year, and a selection of the many of the visitors that this lovely plant hosted throughout the season. Notice that the potential pollinators are generally visiting the yellow disk flowers, those that are still open for business, not the pinkish flowers that have shut down their nectar production.

Bumble Bees are the most frequent visitors.

Bumble Bee (Bombus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Bumble Bee (Bombus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

An athletic Bee drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). I'm not completely sure whether it's a Bumble Bee or an Eastern Carpenter Bee.

An athletic Bee drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). I’m not completely sure whether it’s a Bumble Bee or an Eastern Carpenter Bee.

But many species of Sweat Bees (Halictid bees), and even Honey Bees dine on Blue Wood Aster nectar and pollen.

Sweat Bee (Halictus species) with Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) with Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bee (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A gang of Sweat Bees (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A gang of Sweat Bees (Halictus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bees (Halictid bees) of two different species visiting Blue Wood Aster (Symphyotrichum cordifolium)

Sweat Bees (Halictid bees) of two different species visiting Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Halictid bee) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Halictid bee) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Sweat Bee (Augochlorella species) investigating Blue Wood Aster (Symphyotrichum cordifolium)

A Honey Bee (Apis mellifera) nectaring from Blue Wood Aster (Symphyotrichum cordifolium)

A Honey Bee (Apis mellifera) nectaring from Blue Wood Aster (Symphyotrichum cordifolium)

A Mason Wasp stopped by for nourishment.

A Mason Wasp (Ancistrocerus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Mason Wasp (Ancistrocerus species) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Many fly species paused to drink, most disguised as bees or wasps in an attempt to appear threatening to potential predators.

A Syrphid or Flower fly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower fly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Toxomerous geminatus) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Toxomerous geminatus) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Syrphus ribesii) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Syrphus ribesii) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Sericomyia chrysotoxoides) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Sericomyia chrysotoxoides) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Eristalis tenax) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

A Syrphid or Flower Fly (Eristalis tenax) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Greenbottle Fly (Lucilia sericata) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Greenbottle Fly (Lucilia sericata) drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium)

Even late season butterflies and moths were able to refuel on Blue Wood Aster nectar.

A Clouded Sulphur butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Notice the heart-shaped leaves that are characteristic of this species.

A Clouded Sulphur butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Notice the heart-shaped leaves that are characteristic of this species.

A Pearl Crescent butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Not only do these butterflies benefit from the nectar, but their caterpillars dine on the foliage of several aster species.

A Pearl Crescent butterfly drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium). Not only do these butterflies benefit from the nectar, but their caterpillars dine on the foliage of several aster species.

A Corn Earworm Moth drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium).

A Corn Earworm Moth drinking nectar from Blue Wood Aster (Symphyotrichum cordifolium).

A Yellow-collared Scape Moth (Cisseps fulvicollis) and Bumble Bee on Blue Wood Aster (Symphyotrichum cordifolium).

A Yellow-collared Scape Moth (Cisseps fulvicollis) and Bumble Bee on Blue Wood Aster (Symphyotrichum cordifolium).

Meanwhile, a Brown-hooded Owlet Moth caterpillar dined on the leaves and spent flowers of Blue Wood Aster.

Brown-hooded Owlet caterpillar eating Blue Wood Aster (Symphyotrichum cordifolium) leaves and flowers.

Brown-hooded Owlet caterpillar eating Blue Wood Aster (Symphyotrichum cordifolium) leaves and flowers.

Blue Wood Aster is native in much of the eastern half of the United States, and in British Columbia, Manitoba, Ontario, Quebec, Prince Edward Island and Nova Scotia in Canada. It can be found in a variety of habitats, including woodlands, meadows and roadsides.  There may still be some blooming near you!

 

Related Posts

Asters Yield a Treasure Trove!

New England Asters – A Hotbed of Activity!

Mysterious Bumble Bee Behavior

Resources

Eaton, Eric R.; Kauffman, Ken. Kaufman Field Guide to Insects of North America.  2007.

Eastman, John. The Book of Forest and Thicket.  1992.

Mader, Eric; Shepherd, Matthew; Vaughan, Mace; Black, Scott Hoffman; LeBuhn, Gretchen. Attracting Native Pollinators: Protecting North America’s Bees and Butterflies. 2011.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Wagner, David L.; Caterpillars of Eastern North America, 2005.

Wilson, Joseph S.; Carril, Olivia Messinger. The Bees in Your Backyard. 2016.

USDA NRCS Plant Database

 

Embracing the Shade: Summer and Fall

Is it possible to have a perennial shade garden with continuous bloom throughout the summer and fall?  By June, the trees are fully leafed out, sheltering our home from the summer sun’s strong rays. That means that the garden is in the shade, too. Will anything be blooming? You bet.

Spicebush Swallowtails nectaring on Bottlebrush Buckeye

Spicebush Swallowtails nectaring on Bottlebrush Buckeye

Some spring bloomers, like Heartleaf Foamflower (Tiarella cordifolia) and Virginia Goldenstar (Chrysogonum virginianum), also called Green and Gold, may continue their display into the summer months. While not yet blooming, the leaves of White Wood Aster (Eurybia divaricata) join the violets, ferns, and Spreading Sedge (Carex laxiculmis) to form a ground cover blanketing much of the garden. Arching four to five feet above them are long sprays of Goat’s-beard (Aruncus dioicus) a.k.a. Bride’s Feathers’ tiny white flowers, lighting up the deep shade. June brings Rosebay Rhododendron (Rhododendron maximum) and Wild Hydrangea (Hydrangea arborescens) blossoms, too.

Bottlebrush Buckeye (Aesculus parviflora) is part of the shrub layer in the woods behind our house. In July, this reliable bloomer with its large palmately compound leaves and tall spikes of white tubular flowers attracts Ruby-throated Hummingbirds in addition to Spicebush and Eastern Tiger Swallowtails.

Dark form Eastern Tiger Swallowtail nectaring on Bottlebrush Buckeye

Dark form Eastern Tiger Swallowtail nectaring on Bottlebrush Buckeye

Last summer we were surprised to see dark morph Tiger Swallowtails nectaring on the Bottlebrush Buckeye. By adopting this Pipevine Swallowtail-like coloration disguise, the Tiger Swallowtails gain some protection from being eaten by birds and other predators who have learned of the Pipevine Swallowtail’s toxicity. The dark morph occurs most frequently in areas where Pipevine Swallowtails are present. Maybe Dutchman’s Pipevine (Aristolochia macrophylla) and its namesake swallowtail are increasing in our area!

Courting Zabulon Skippers on Purple Giant Hyssop

Courting Zabulon Skippers on Purple Giant Hyssop

July is also the beginning of Purple Giant Hyssop’s (Agastache scrophulariifolia) long bloom, lasting well into September. We have it in both deep shade and a spot that gets a few hours of afternoon sun, blooming dependably in both locations. This herbaceous plant is a great choice for a woodland garden, with a growth form that is similar to Butterfly Bush. In our garden, butterflies from the smallest skippers to the largest swallowtails love Purple Giant Hyssop. Bees love it, too, and even hummingbirds may drink from the nectar-packed purple flowers.

Eastern Tiger Swallowtail nectaring on Purple Giant Hyssop

Eastern Tiger Swallowtail nectaring on Purple Giant Hyssop

Pollinators can’t resist Mountain Mints.

Sweat Bee (Lasioglossum species) on Short-toothed Mountain Mint

Sweat Bee (Lasioglossum species) on Short-toothed Mountain Mint

I decided to try Short-toothed Mountain Mint (Pycnanthemum muticum), also called Clustered Mountain Mint, the only one of the Mountain Mint (Pycnanthemum) species I thought could tolerate some shade. I put it in the one location that gets about four hours of afternoon sun, and I got lucky. While not as robust as it would be in a sunnier spot, it’s doing well, its tiny magenta and white blossoms enticing the smaller butterflies like azures and skippers throughout July and August.

Summer Azure nectaring on Short-toothed Mountain Mint

Summer Azure nectaring on Short-toothed Mountain Mint

As summer progresses, False Sunflower (Heliopsis helianthoides) radiates bright yellow sunbursts at the wood’s edge from July well into September.

Sweat Bee (Agapostemom species) on False Sunflower (Heliopsis helianthoides)

Sweat Bee (Agapostemom species) on False Sunflower (Heliopsis helianthoides)

Eastern Tiger Swallowtails and Bumble Bees are frequent diners at Great Blue Lobelia (Lobelia siphilitica), open for business during August and September.  Even Ruby-throated Hummingbirds will stop here for a drink.

Eastern Tiger Swallowtail nectaring on Great Blue Lobelia

Eastern Tiger Swallowtail nectaring on Great Blue Lobelia

Also in August, after gathering energy from the sun from the earliest spring days when its leaves begin to emerge, White Wood Aster blinks on its light show of white blossoms, illuminating the dense shade through October. The delicate blue disk flowers of Carolina Elephantsfoot (Elephantopus carolinianus) provide a complementary offset in August and September.

White Wood Aster

White Wood Aster

Butterfly traffic slows by September, but Black Swallowtails may still lay eggs this late, sometimes on my cooking herbs (parsley and dill).

Black Swallowtail caterpillar eating parsley

Black Swallowtail caterpillar eating parsley

Last fall we hosted a chrysalis on a hot pepper plant.

Black Swallowtail chrysalis on pepper plant

Black Swallowtail chrysalis on pepper plant

More aster family members begin their fall performance now, including Blue Wood Aster (Symphyotrichum cordifolium),

Blue Wood Aster with Bumble Bee

Blue Wood Aster with Bumble Bee

Wreath Goldenrod (Solidago caesia),

Wreath Goldenrod

Wreath Goldenrod

and Zigzag Goldenrod (Solidago flexicaulis), in bloom and offering nectar through October or early November. Like White Wood Aster, all of the foliage of these species emerged in early spring from the winter’s leaf cover.

All of these summer and fall blooming species have a reproductive strategy that includes clusters or spikes of flowers that bloom gradually over a period of many weeks, increasing each plant’s chances of pollination by bees, butterflies, and others, and resulting in a long colorful garden display.When successfully pollinated, Purple Giant Hyssop, Carolina Elephantsfoot and Woodland Sunflower offer Chickadees, Goldfinches and other birds a fall bounty of food.

Goldfinch eating Elephant's Foot seeds

Goldfinch eating Elephant’s Foot seeds

Resident and migrant birds dine on the bright red fruit of Spicebush (Lindera benzoin) and Flowering Dogwood (Cornus florida) and the dark blue fruit of Sassafras (Sassafras albidum) and Blackhaw Viburnum (Viburnum prunifolium). This is after a busy season of acting as caterpillar food plants – Spicebush and Sassafras for Spicebush Swallowtails, Flowering Dogwood and Blackhaw for Spring Azures.

Flowering Dogwood fruit

Flowering Dogwood fruit

In October and November, Witch-hazel’s (Hamamelis virginiana) spidery yellow blossoms complement the fall foliage.

Witch-hazel flowers and fruits

Witch-hazel flowers and fruits

The bright red fruits of Winterberry Holly (Ilex verticillata) may last until late winter, when hungry birds finally eat them.

Winterberry Holly berries

Winterberry Holly berries

Little maintenance is required in this woodland garden. Because the plants have filled in to form a ground cover in most places, there is little weeding to do. We primarily use naturally fallen leaves as mulch, although we may supplement with a bit of prepared leaf compost around the front edges, in deference to our homeowners’ association’s sensibilities.

When we were trying to grow lawn in the shade, it was sparse, and we had problems with standing water after a heavy rainfall. Not anymore. The trees, shrubs and other plants in the garden, as well as the leaf litter, help the soil to absorb rainfall. The shade keeps the soil from drying out too quickly. So once these plants are established, watering is only required when drought conditions become extreme.

Not a bad performance for a woodland garden. And it brings so much pleasure!

Notes:

This is part 3 of a 3 part series.  To see parts 1 & 2, see A Butterfly Garden That Embraces the Shade and  A Butterfly Garden That Embraces the Shade – Spring.

This post was adapted from an article that was originally published in the Summer 2013 issue of Butterfly Gardener, a publication of the North American Butterfly Association.

Asters Yield A Treasure Trove!

Orange Sulphur on New England Aster (Symphyotrichum novae-angliae)

Orange Sulphur on New England Aster (Symphyotrichum novae-angliae)

A few days ago the weather was beautiful, with temperatures in the mid-60s, cloudless blue skies and a bit of a breeze, so we went for a walk at a wildlife management area in West Amwell, New Jersey.  We were looking for birds, fall fruit and foliage, and any other interesting critters that happened to present themselves.

We didn’t expect to see a lot in the way of butterflies because of the cool temperatures, and because it’s so late in the season.  We didn’t see many butterflies, but those we did see were pretty spectacular.  Orange Sulphurs were out and about, which was to be expected, since they are among the species that stay active as late as November in this area.  But the surprises were a Fiery Skipper and an American Snout, both of which are fairly rare in New Jersey, especially in late October.  All were nectaring on various species of asters, or other aster family members, the goldenrods.

American Snout

American Snout

Fiery Skipper on New England Aster (Symphyotrichum novae-angliae)

Fiery Skipper on New England Aster (Symphyotrichum novae-angliae)

Asters family members are the primary source of food for late season pollinators.  They are prolific in their long bloom period, often continuing into November.  Their flowering structure reflects a very clever strategy, and suggests this plant family’s alternate name, ‘composite’.  What looks to us like a single flower is actually a cluster of tiny flowers, potentially of two different types, ray flowers and disk flowers.

Blue Wood Aster (Symphyotrichum cordifolium)

Blue Wood Aster (Symphyotrichum cordifolium)

The photograph above of Blue Wood Aster (Symphyotrichum cordifolium) shows the classic flower heads of the Aster family:  a circle of ray flowers that look like petals, pale blue in this species, surrounding a cluster of tiny tubular disk flowers in the center of the head.  If you look carefully at the disk flowers in this photo, you can see that the outer rows are open and blooming, while those in the center of the cluster are still in bud.  This gradual bloom habit supports a long period of flowering, offering nectar to fall pollinators for many weeks.  The disk flowers of this plant are a pale yellow in bud and when they first open, then turning pink or magenta as they age.  This color change is thought to be a signal to pollinators, directing them to the receptive yellow flowers which are not yet pollinated and that will reward them with nectar, and steering them away from those blossoms that are already satisfactorily pollinated.  (Plants are so clever!)  Notice the pink and magenta disk flowers in some of the flower heads in this photo.

As soon as the temperature gets into the low 50s on these crisp late October mornings, the Bumble Bees begin foraging on billowing clouds of luminous Blue Wood Asters outside my windows, soon joined by other tiny bees and flies.  Large dense clusters of bright pale blue flowers top the heart-leaved covered stalks of this woodland beauty.  The shape of the leaves is reflected in the species name, cordifolium, and also gives this plant another commonly used name, Heart-leaved Aster.  Pair Blue Wood Aster with White Wood Aster (Eurybia divaricata) and Wreath (Bluestem) Goldenrod (Solidago caesia) or Zigzag Goldenrod (Solidago flexicaulis) for a spectacular late season shade garden display.

New England Aster (Symphyotrichum novae-angliae)

New England Aster (Symphyotrichum novae-angliae)

Favorites for a sunny garden or meadow include New England Aster (Symphyotrichum novae-angliae), which is also seen blooming in many spots along roadsides, and Aromatic Aster (Symphyotrichum oblongifolium), whose intense blue flowers are irresistible to insects and humans alike.

Following are more asters and their visitors.  You never know what treasures asters will yield!

Flower or Hover Fly, Helophilus sp, on Aromatic Aster (Symphyotrichum oblongifolium)

Flower or Hover Fly, Helophilus sp, on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Aromatic Aster (Symphyotrichum oblongifolium)

Orange Sulphur on Awl Aster (Symphyotrichum pilosum)

Orange Sulphur on Awl Aster (Symphyotrichum pilosum)

Hover or Flower Fly, likely Toxomerus geminatus, on Aromatic Aster (Symphyotrichum oblongifolium)

Hover or Flower Fly, likely Toxomerus geminatus, on Aromatic Aster (Symphyotrichum oblongifolium)

Blue Wood Aster (Symphyotrichum cordifolium) with Bumble Bee

Blue Wood Aster (Symphyotrichum cordifolium) with Bumble Bee

Aromatic Aster (Symphyotrichum oblongifolium) with Common Buckeye

Aromatic Aster (Symphyotrichum oblongifolium) with Common Buckeye

Common Checkered Skipper on Aster

Common Checkered Skipper on Aster

Mating Bees on Aromatic Aster (Symphyotrichum oblongifolium)

Mating Bees on Aromatic Aster (Symphyotrichum oblongifolium)