Jewelweeds and Popping Seeds

  

Flowers of Orange Jewelweed (Impatiens capensis).
Rowan County, North Carolina. 

Jewelweeds put on a fantastic show in the fall.  They produce large stands of bright flowers at a time when other plants are fading.  We are blessed with two native species of Jewelweed (Impatiens) in Eastern North America, Impatiens capensis and Impatiens pallida. Both species of Jewelweed are herbaceous, with translucent, succulent stems.  Their leaves are coated with a waxy layer and water drops make jewel-like beads on the surface. 

 

Beads of water on Orange Jewelweed leaves.
Rowan County, North Carolina. 

Jewelweeds flower in late summer and fall. They are pollinated by hummingbirds and bees.  Jewelweed  flowers have a spur extending from the back of the flower with a nectary at the end of the spur.  Hummingbirds seeking nectar push their beaks deep into the spur and collect pollen on their faces to take to the next flower.  Bee pollinated flowers have a slightly different spur structure than those pollinated by humming birds.  Hummingbird flowers have a curved spur but the bee pollinated spur turns down at a 90-degree angle. The peak of Jewelweed flowering comes as the Ruby-throated Hummingbirds (Archilocus colurbris) are beginning their migration south and need a lot of energy.  

Orange Jewelweed flower as its pollinators see it.  
Rowan County, North Carolina. 

Impatiens capensis has a number of common names including Orange Jewelweed and Spotted Touch-me-not.  The flowers are orange and yellow with darker spots.  This annual grows in moist soil along streams, forest understories and ditches. Orange Jewelweed is used in traditional medicine to treat poison ivy, bee and nettle stings.  

Orange Jewelweed from the side.  This flower has a curved spur at the
back indicating a hummingbird would be most successful pollinating this flower. 
Blue Ridge Parkway, Watauga County, North Carolina.  

The fruits of Orange Jewelweed are up to an inch long and have a surprising way to disperse their seeds.  If you touch a mature fruit of Jewelweed it will explode in your hand, throwing seeds up to ten feet from the parent plant.  This violent spreading of seeds is called ballistic seed dispersal and is powered by tension in the fruit wall.  An animal brushing the plant, a raindrop or even a slight breeze will cause a shower of flying seeds.  Ballistic seed dispersal is what gives this Jewelweed one its common names, Spotted Touch-me-not. It is as if the plant does not want to be touched and pops seeds in protest. When our kids were young they liked to make Jewelweed fruits explode on our mountain hikes during the fall.  They came up with their own name for this plant, Poppy-heads.

Orange Jewelweed fruit.
Rowan County, North Carolina.

Isolated Orange Jewelweed fruit.  The fruit wall is under tension
and primed to explode. 
Rowan County, North Carolina. 

The fruit from above after exploding.
Rowan County, North Carolina. 

Video of Orange Jewelweed explosive seed dispersal.

Rowan County, North Carolina. 

Impatiens pallida, Yellow Jewelweed, is a close relative of Orange Jewelweed and has many of the same characteristics.  The most obvious difference is flower color, which in this species is pale yellow.  In our area, Yellow Jewelweed grows mainly in the mountains while Orange Jewelweed is found throughout.

Yellow Jewelweed (Impatiens pallida) flower viewed from the front.
Blue Ridge Parkway, Watauga County, North Carolina. 

Yellow Jewelweed flower seen from the side. 
The spur on this flower is perpendicular so  
this flower is most likely to be pollinated by a bee. 
Blue Ridge Parkway, Watauga County, North Carolina. 

Jewelweeds flowers are a sign of fall.  In October I found large numbers of Green Stinkbug (Chinavia hilaris) nymphs on Orange Jewelweed.  These bugs lay their eggs on Jewelweed and the nymph stages develop on the plant until they molt into adults and fly away.  Jewelweeds are killed by the first frost but grow again the following spring from the multitude of seeds the plants threw out.

Green Stink Bug (Chinavia hilaris) nymph on Orange Jewelweed.
Rowan County, North Carolina. 

Orange Jewelweed
Blue Ridge Parkway, Watauga County, North Carolina. 

Pollinators

 

Zebra Swallowtail (Protographum marcellus) pollinating
Lantana camara.  Rowan County, North Carolina.

Pollinators are hot.  There are pollinator gardens, pollinator workshops, pollinator blogs, pollinator TED talks and pollinator podcasts. The reason for all this interest is pollinators are so darn interesting.  Pollinators are animals that transfer pollen between flowers to produce a next generation of plants.  Many animals act as pollinators including; ants, beetles, bees, wasps, moths, butterflies, hummingbirds and bats.  Most flowers that rely on pollinators have conspicuous flowers to attract pollinators and produce nectar as a payoff to the pollinating animals.  

In this edition of the blog I will discuss pollinators that have come to the gardens at our house and to the Rowan County Extension Master Gardeners Pollinator Garden. 

Bees and Wasps

Blue-winged Scoliid Wasp (Scolia dubia). 
This wasp has a red abdomen with two yellow spots.
Rowan County, North Carolina.

Golden-reined Digger Wasp (Sphex habenus).
Rowan County, North Carolina. 

Carpenter Bee (Xylocopa virginica).  This bee is a male, marked 
by the black spot on the top of the thorax. 
Rowan County, North Carolina. 

Thousands of species of bees and wasps act as pollinators.  These insects often pollinate flowers that have a landing platform and deliver pollen to the back of the bee as they seek nectar deep in the flower.  Sometimes Carpenter Bees (genus Xylocopa) are nectar robbers.  The shape of some flowers do not allow the Carpenter Bees to reach the nectar and pick up pollen, so they drill into the base of the flower, drink nectar and bypass the pollen all together.  

Carpenter Bee robbing nectar from Black and Blue Sage
(Salvia guaranitica). The bee is cutting a hole in the
base of the flower with its bright red mouth parts to steal nectar. 
Rowan County, North Carolina.

Bumblebee (Bombus impatiens) covered with pollen from
Gaillardia aristata. 
Rowan County, North Carolina. 

The Black-tailed Bee Fly (Bombylius major) is really a fly that looks like a bee.  It has a fuzzy yellow and black abdomen and looks very bee-like at first glance.  The Black-tailed Bee Fly can hover like a bee and insert its long proboscis into flowers picking up pollen as it does.  

Black-tailed Bee Fly (Bombylius major) is a fly that mimics bees. 
This one is feeding on Lantana. 
Rowan County, North Carolina. 

Moths

Most moths fly at night and typical moth pollinated flowers are white and produce a strong fragrance to attract the insects.  Sphinx Moths are large moths that come to our yard to pollinate Datura wrightii, Jimson Weed.  These moths lay their eggs on tomato plants their larvae are the gigantic and destructive Tomato Hornworms.

Five-spotted Hawk Moth (Manduca quinquemaculata), a 
Sphinx Moth, pollinating Jimson Weed (Datura wrightii).
Rowan County, North Carolina.

A handful of moths fly by day are easily seen in gardens.  Among the most conspicuous of these are the Hummingbird Moths.  These large moths mimic both hummingbirds and bumblebees in their coloration and behavior. In late summer we have large numbers Hummingbird Moths including the Snowberry Clearwings (Hermaris diffinis) on our Lantana plants.    

Snowberry Clearwing (Hermaris diffinis) pollinating Lantana.
Rowan County, North Carolina.  

One of the most beautiful day-flying moths is the Ailanthus Webworm Moth (Atteva aurea).  This moth is native to south Florida and the American tropics. It has expanded its range to much of the eastern United States by using the invasive Tree of Heaven (Ailanthus altimissa) as a host.  Despite its attraction to an undesirable tree, this moth is a welcome visitor with its beautiful orange, white and black color scheme.  

Ailanthus Webworm Moth (Atteva aurea).
Rowan County, North Carolina. 

Butterflies 

Eastern Tiger Swallowtail (Papilio glaucus). This yellow form of the
species shows the stripes that gives it its common name.
Rowan County, North Carolina. 

The dazzling colors and dramatic shapes of butterflies are a major reason for the popularity of pollinator gardens.  Plants in these gardens serve as both a source of nectar for adult butterflies and a host plant for larvae.  From the large Eastern Tiger Swallowtail (Papilio glaucus) to the tiny Red-lined Hairstreak (Calycopis cecrops), butterflies are with us throughout the flowering season. Butterflies usually sip nectar from flowers that have a landing platform and dip their long proboscis into the flower.  They accidently collect pollen that can be transferred to the next plant they visit.  

The dark form of the Eastern Tiger Swallowtail occurs
in a significant percentage females. In these butterflies
the yellow areas are replaced by black. 
Rowan County, North Carolina.

Zebra Swallowtail has black and white stripes, thus zebra in its name.
Rowan County, North Carolina. 

Gulf Fritillary (Dione vanillae) is a large, colorful butterfly found
across the southern tier of the United States.
Rowan County, North Carolina.

Gulf Fritillary seen from below.
Rowan County, North Carolina.

Common Buckeyes (Junonia coenia) are found across most of North America.
The eyespots on the wings are used to startle predators.
Rowan County, North Carolina.  

Red-banded Hairstreak (Calycopis cecrops). This butterfly has an
interesting protective adaptation.  There are two tails (the hairstreaks)
on each hindwing that resemble antennae.  They also have an
eyespot on each hindwing and combined with the hairstreaks it
appears the head of the butterfly is located at the posterior end. 
When predators attack the false head, 
the Red-banded Hairstreak can fly away.
Rowan County, North Carolina.  

Monarch Butterfly (Danaus plexippus) on
Tropical Milkweed (Asclepias curassavica)
Rowan County, North Carolina.

Skippers are an interesting group of butterflies.  They are usually small, drab colored and get their name from their rapid flight.  Many species of skippers hold their front pair of wings vertically when perched.  At one time scientists thought skippers were intermediate between moths and butterflies but it is now well established they are true butterflies.  

Silver-spotted Skipper (Epargyreus clarus) on Lantana.
This large skipper has gold and silver spots on the wings.
Rowan County, North Carolina.

Fiery Skippers (Hylephlia phyleus). These small
skippers are perched on a milkweed fruit. 
Rowan County, North Carolina. 

Juvenal's Duskywing (Erynnis juvenalis) is a small, dark skipper.
Rowan County, North Carolina.  

Long-tailed Skipper (Urbanus proteus) is a large, blue-bodied
skipper with long tails on its wings.
Rowan County, North Carolina. 

Hummingbirds

In eastern North America the common hummingbird is the Ruby-throated Hummingbird (Archilochus colubris).  These tiny dynamos are marvels.  They are only three inches long and weigh less than half a gram but can fly at 25 miles per hour, beat their wings 50 times per second and can fly, non-stop across the Gulf of Mexico during migration.  Ruby-throated Hummingbirds feed on nectar and are particularly attracted to red flowers.  Hummingbird flowers usually have a long tube with nectar at the base.  While feeding, the bird gets pollen on its feathers and beak.  The hummingbird then inadvertently pollenates the next flower. In our yard, the hummingbirds visit Salvias, Inpatients, Hibiscus and Columbines. 

 

A female Ruby-throated Hummingbird (Archilochus colubris).
Hummingbirds drink nectar while hovering and
coincidently pollinate flowers.
Rowan County, North Carolina. 

Besides being intrinsically interesting, pollinators are getting a lot of attention because they are in trouble.  This trouble stems from a roll call of the usual suspects; habitat fragmentation and loss, pesticide use, non-native plants and climate change.  To counter this formidable list of problems, people are planting pollinator gardens, replacing non-native landscape shrubs and trees with natives, removing invasive plant species and providing nest sites. By taking these steps people can improve the number and diversity of pollinators in their yard and in their town.  It is not just good for planet it is also a grand show.