Spicebush or Forsythia?

For the past few weeks, Spicebush (Lindera benzoin) buds looked like they couldn’t wait to open.  Over the weekend when the temperatures reached 80°F in the latest round of weather whiplash, the buds burst open, resulting in a display of bright yellow starbursts lighting up the forest understory.

Spicebush (Lindera benzoin) in bloom, with ant seeking nectar

Spicebush (Lindera benzoin) in bloom, with ant seeking nectar

Spring temperatures have a big influence on the exact timing, but where I live in the mid-Atlantic United States, Spicebush typically blooms in late March or early April, at about the same time as forsythia.  Forsythia is also lovely for the ten days or so that it’s in bloom, but then it’s a little, well, boring, when compared to Spicebush.

Sometimes called Northern Spicebush or Common Spicebush, this shrub is native in the north from Maine to Ontario, Michigan, Iowa and Kansas, then its range extends south to Texas and throughout the southeastern United States to Florida. It can generally be found in woodlands, but works well as a landscape plant, too. Spicebush gets its common name from the spicy aroma emitted from its leaves and young branches when they are rubbed or crushed.

Where Spicebush is native, it has important relationships with animals that have evolved with it over the centuries. Many insects, including early butterflies, visit the flowers for nectar, but early solitary bees and flies are the primary pollinators.

Spicebush (Lindera benzoin) with Spring Azure butterfly nectaring

Spicebush (Lindera benzoin) with Spring Azure butterfly nectaring

The flowers bloom before the leaves unfurl, making it easy for pollinators to find them. Spicebush has male and female flowers on separate plants.

Male Spicebush flowers; note yellow pollen like little balls at tips of stamens

Male Spicebush flowers; note yellow pollen like little balls at tips of stamens

Female Spicebush flowers; note pistils protruding beyond the petals

Female Spicebush flowers; note pistils protruding beyond the petals

So if you are using them in your landscape, you will want a male to pollinate the female plants in order to see the bright red fruits that complement this shrub’s yellow fall foliage.

Spicebush (Lindera benzoin) fall fruit and foliage

Spicebush (Lindera benzoin) fall fruit and foliage

Many birds eat the fruit, but Veeries

Veery

Veery

and Wood Thrushes,

Wood Thrush

Wood Thrush

birds that are often found in the same habitat as Spicebush, are especially partial to them.

Spicebush Swallowtail butterflies are often seen nectaring on flowers in sunny locations,

Spicebush Swallowtail nectaring on Wild Bergamot (Monarda fistulosa)

Spicebush Swallowtail nectaring on Wild Bergamot (Monarda fistulosa)

but they can also be found in the woods in the vicinity of their namesake plant, Spicebush. This is because the primary food plants for Spicebush Swallowtail caterpillars are Spicebush (Lindera benzoin and in the southern U.S., also L. melissifolia) and the related Sassafras (Sassafras albidum), which is usually found in the same type of habitat. Without these plants we wouldn’t have this lovely butterfly, since its caterpillars can only survive on the leaves of a few plant species.

Female Spicebush Swallowtails lay their eggs singly on the underside of a leaf.

Spicebush Swallowtail egg

Spicebush Swallowtail egg

After the caterpillars hatch from the eggs, they depend on the leaves of these plants for both food and shelter. Each caterpillar eats a few leaves of a Spicebush during its development.

Spicebush Swallowtail caterpillar; notice the evidence of feeding on the leaf in the lower right corner

Spicebush Swallowtail caterpillar; notice the evidence of feeding on the leaf in the lower right corner

Looking for holes in leaves is one way to find these caterpillars.  But we’re not the only creatures who have figured out this strategy for locating them. Caterpillars and other insects are an important source of food for birds, especially when the birds are raising their young.  Some bird species also know enough to look for partially eaten leaves to point them to a tasty meal of caterpillar protein.

Tufted Titmouse, looking for a meal

Tufted Titmouse, looking for a meal

So the caterpillars have evolved to protect themselves by destroying the evidence of their dining experience. While I watched, this caterpillar crawled to the stem of the leaf it had been eating. It chewed through the stem, and the incriminating evidence, the partially eaten leaf, fell to the ground.

Spicebush Swallowtail caterpillar, destroying the evidence of its presence by chewing through the leaf stem

Spicebush Swallowtail caterpillar, destroying the evidence of its presence by chewing through the leaf stem

Spicebush Swallowtail caterpillars have other strategies to protect themselves from predators. In their earliest growth stages they look like bird droppings, a clever disguise to deter birds from eating them. As they grow, they take on the appearance of a snake, with false eye spots above their real head. This snake disguise is an effective deterrent to at least some of the birds that might otherwise eat the caterpillars, since snakes are the birds’ predators in their wintering grounds.

Black-Throated Blue Warblers may be put off by a snake-like disguised caterpillar

Black-Throated Blue Warblers may be put off by a snake-like disguised caterpillar

When they’re not eating, Spicebush Swallowtail caterpillars hide in leaf shelters that they create for themselves by spinning silk to pull two sides of a leaf together.

Spicebush Swallowtail caterpillar using its silk to create a leaf shelter

Spicebush Swallowtail caterpillar using its silk to create a leaf shelter

Spicebush is also a food plant for the caterpillars of a moth called the Tulip-tree Beauty,

Tulip-tree Beauty caterpillar on Spicebush (Lindera benzoin)

Tulip-tree Beauty caterpillar on Spicebush (Lindera benzoin)

and one of the giant silk moths, the Promethea Moth.

Promethea Moth Caterpillars on Spicebush

Promethea Moth Caterpillars on Spicebush

Winter is a good time to look for Spicebush Swallowtail chrysalises and Promethea Moth cocoons, since these species overwinter as pupae.

Forsythia on the other hand, primarily a native of Asia, doesn’t support any of our native insects and birds in this way.  So I’m opting for Spicebush.

Spicebush (Lindera benzoin)

Spicebush (Lindera benzoin)

Related Posts

A Promethea Moth and the Awe-inspiring Power of Nature

Resources

Butterflies and Moths of North America
http://www.butterfliesandmoths.org/

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

Illinois Wildflowers http://www.illinoiswildflowers.info/trees/plants/spicebush.htm

Natural History Museum Database of Leipidoptera Hostplants
http://www.nhm.ac.uk/research-curation/research/projects/hostplants/

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.