Wednesday, August 5, 2015

Wednesday's Wildflower: Thinleaf Coneflower

All across America can be found bright yellow or orange flowers with dark centers.

Most everyone is pretty familiar with the Rudbeckia genus, even if they only know them by their common name, Black-eyed Susans.

However, there are at least 25 species to be found in our country, including today's subject: the Thinleaf Coneflower.

It can be found growing in the Midwest and throughout the entire Eastern half of North America, forming dense stands in thickets and woodland edges wherever the soil is damp.

In Middle Tennessee, this is a flower indicative of late Summer and early Fall; usually beginning its bloom in July and continuing through October.

Like other members of their genus, they can be recognized by their bright yellow-orange rays and dark, cone-shaped disks.

R. triloba can also be recognized by its sharp-pointed bracts located next to each disc flower
The disks are where the true flowers are located, and can be brown or even dark purple.

The individual flowers are short-lived, but open in a continuous procession. They tend to look a little ratty as they age, but the pristine, newly opened flowers are quite lovely.

Thinleaf Coneflower has a highly branched growth habit, reaching heights of 5 feet. Their stems are hairy, but not as bristly as other Rudbeckia species.

The leaves are the most distinctive feature. The basal leaves are usually deeply lobed, often 3-lobed, and the alternating stem leaves are thin and toothed.

In fact, Rudbeckia's Latin name, R. triloba means, not surprisingly, "3-lobed."

Thinleaf coneflower is often found alongside its common companions: Joe-Pye Weed, Cardinal Flower and Tall Ironweed.

Their flowers compliment one another beautifully, and I have many great memories growing up of picking bouquets of these wildflowers and taking them home to adorn our kitchen table.

The genus Rudbeckia was named in honor of the Swedish professor, Olaf Rudbeck (1630-1702).

Many of the Rudbeckia genus have provided good medicine for mankind throughout the ages.

Both R. hirta and R. fulgida have been used by native tribes in a variety of ways:

The root sap was used to relieve an earache. Skin sores were bathed in a warm root tea. Root tea was also consumed to treat venereal diseases. The plants were made into a wash that was applied to snake bites, and taken internally to relieve symptoms from intestinal parasites.

Rudbeckia species are also beneficial to wildlife. Birds, especially Goldfinches, enjoy eating the seeds. 

Pollinators of many types are attracted to the flowers, including Hoverflies, which are excellent for controlling garden pests.

A variety of bees and butterflies visit them too.

A Lace-winged Roadside skipper
The foliage is browsed by deer, and also provides larval food plants for several types of butterfly caterpillars, like Silvery Checkerspots.

I've mentioned several times before how the beautiful petals of the ray flowers aren't the "true flowers," but bright beacons to guide pollinators to the pollen and nectar within, aiding the plant in its reproduction.

They may seem bright enough to us, but until scientists began observing flowers under ultraviolet light, we had no idea what the pollinators were actually seeing.

Fine Art America
These are Black-eyed Susans photographed in ultraviolet light, and you can see the strong pattern directing the pollinators to the center of the flower. 

In fact, almost every species of flower has some type of invisible (to us) pattern. Even the humble Dandelion:

Larval Subjects
Most pollinators can view the ultraviolet spectrum, and use these patterns as landing platforms, guiding them to the nectar.

Nature is always full of surprises! this little Crab Spider hoping to surprise a pollinator!
Needless to say, Rudbeckia species make an excellent garden plant. They are generally non-fussy, especially if given plenty of sunshine and reasonably moist soil.

This is Rudbeckia fulgida that I have planted in my flower bed
When looking for a Rudbeckia to add to your landscaping, try to find the straight species, rather than a fancy cultivar. This insures that the beneficial qualities haven't been bred out of them.

I wish I could say they are deer-proof, but they do seem to really enjoy them, when given the opportunity. (But then, practically any plant is fair game in over-populated areas.)

The deer have been browsing R. triloba pretty heavily at my parents' farm
While the deer may browse on them, some Rudbeckia species are reported to be toxic to sheep, cattle and pigs.

This fine plant family is a Summer favorite of many, easily recognized and enjoyed by humans and wildlife, alike.

The Thinleaf Coneflower is merrily blazing away in the woods near my home - hinting that the end of summer is in sight, and to enjoy the warmth while it lasts.

Be sure to join us for next Wednesday's wildflower!

Click here to read about last week's wildflower, Virgin's Bower

Medicinal information herein is shared strictly for anecdotal purposes. Do not attempt to self-medicate with wild herbs. Please consult a doctor first.

Next flower->


Wildflowers of Tennessee, the Ohio Valley and the Southern Appalachians - Dennis Horn & Tavia Cathcart

Cherokee Plants and their Uses - a 400 Year History - Paul B. Hamel & Mary U. Chiltoskey

All About Tennessee Wildflowers - Jan W. Midgley


  1. Such a happy flower! Thanks for the great info. Thanks for sharing at the Weekend Blog Hop at My Flagstaff Home!


  2. These are very pretty. Love your detailed descriptions!

    Thanks for linking up with Green Thumb Thursday! I'd love to see you back this week!