Wednesday, September 23, 2015

Wednesday's Wildflower: Field Thistle

We don't tend to think of plants as prey items, but they are, essentially.

They are at the mercy of everything from insects to ungulates to us, tearing them limb from limb and munching on their delicate parts.

Just like animal prey, plants have had to come up with ways to "fight back."

Some produce toxins to make their bodies unpalatable to herbivores, while others have developed irritating oils or hairs.

Thistles, of course, arm themselves with prickles.

They are members of the broad-reaching and distinguished Aster family, or Asteraceae, organized into two genera: Carduus and Cirsium.

At least 60 species of thistle can be found in North America, with several of them having been introduced, primarily from Europe.

The Nodding Thistle (Carduus nutans) was introduced from Eurasia
One of our native thistles is the Field Thistle, and its pale purple blooms float like clouds amidst a sea of yellow and white.

Found across much of the eastern United States, it likes sunny locations with mesic soil: abandoned fields, dry prairies, limestone glades, roadsides, powerline right-of-ways and moist meadows adjacent to rivers. It occurs most abundantly in recently disturbed habitats.

It is a biennial (completing its life cycle in two years) or short lived perennial, typically growing from 3 to 7 feet tall.

It has a hairy stem, and numerous leaves that are divided into deep, spiny lobes.

The undersides of the leaves are pale white, distinguishing them from similar thistle species.

Plants have few to several flower heads measuring 2 inches across, purplish-pink in color.

The overlapping bracts under the flowers are known as phyllaries, and are striped with light green central veins and tipped with thin, golden spines.

Field Thistles begin their bloom in late summer and continue into October.

They are also known by the names Pasture Thistle and Bicolor Thistle.

Their Latin name is Cirsium discolor. The genus, Cirsium, comes from the word circos, meaning "swollen vein," which is a malady thistles were once thought to cure. Discolor simply means "two different colors," in reference to its two-toned leaves.

A similar species that can cause confusion is the Bull Thistle (Cirsium vulgare), a plant introduced from Europe and naturalized across our entire continent, often making quite a pest of itself.

Wikipedia Commons
It has the same formidable defenses as the Field Thistle, but there are some subtle differences.

Bull Thistle flowers are a darker purple, and the phyllaries lack the pale central vein. The spines that cover the bracts are much coarser and more numerous than those of the Field Thistle.

They are also far more invasive.

Wikipedia Commons
The Bull Thistle is thought to be responsible for the famous Scottish legend, ultimately leading to its veneration as Scotland's official symbol.

As the story goes, an invading Norse army was attempting to sneak into a Scottish army encampment, when one barefoot Norseman happened to step on a thistle and cry out in pain, alerting the Scottish army to their presence and giving them victory over the invaders.

The type of thistle that pricked the Norseman's foot has been a subject of fierce debate for centuries, but Cirsium vulgare would have been the most likely culprit for that location and time period.

Despite the thistle's formidable defenses, the plant is considered a fine edible.

In fact, all true thistles (in the genera Cirsium and Carduus) are edible, though their palatability does vary between species.

The leaves can be eaten, but of course require the snipping off of spines, which can be a little too labor intensive for some, but are said to be good raw or cooked.

The roots can be harvested and eaten in mature plants, just be aware that they are high in the starch inulin, which we cannot digest - so they may have a bit of a, er - windy effect.

The core of unopened flower buds is also said to be good cooked and squeezed out. (But only if you want a lot of work for little reward.)

Feral Kevin
The tastiest part of the plant is said to be the inner core of the young stalks from two-year-old plants.

Harvesting, of course, takes a little care.

Thick gloves are necessary, and you might wish to bring along newspaper to wrap the plants in once you've cut them (unless you decide to disarm them in the field).

Simply take a sharp knife, pruning shears or even a shovel blade and cut the plant just above the basal leaves.

Holding it in a gloved hand, you can then snip off the spiny leaves with sharp scissors or shave them off with a sharp knife.

To get to the tender core, peel the fibrous stalk until you start to see white.

Feral Kevin
An alternative is simply to roast it whole and then squeeze out the cooked core.

Younger stalks (before flowering) can be eaten raw as a salad green, and older stalks are great steamed or boiled and served with butter.

The seeds can be eaten, but some sources state that they can contain toxic alkaloids, so please use caution. You can also extract oil from them - 12 pounds of seed will yield 3 pounds of oil suitable for cooking or lamp oil.

Here is a YouTube video demonstrating another harvesting method, simply using a large knife:

The thistle they are harvesting is Cirsium horridulum, or Yellow Thistle - a common weed in overgrazed pastures that is one of the better eating thistle species.

If you prefer not to harvest a plant that fights back, there is one thistle you can occasionally find at your local supermarket, and indeed you may have eaten it before: 

Plant Village
the artichoke.

Bonnie Plants
Thistles are useful for much more than just food.

Older stalks are very fibrous, and can be used as cordage or even paper. You can extract the fibers by soaking the plants in water for several days.

The Seminole Indians made blowgun darts out of thistle spines, and the seed down was used as guides for the darts.

Dry seed fluff also makes great tinder for starting fires, easily lit by a spark from flint.

The dried flowers can even be used as a rennet substitute for curdling milk. (You can read more about that here.)

Thistles have also been an important source of healing medicine throughout our history.

The roots were used in a poultice to treat a sore jaw.

A warm infusion of the whole plant was used in the treatment of rheumatic joints.

A whole plant decoction was used both internally and externally to treat bleeding hemorrhoids.

Even though its defenses are useful against most herbivores, sometimes goats or burros will make a meal out of them.

The foliage also provides food and shelter for several species of butterfly caterpillar, such as the Painted Lady.

Field thistles are a major late-season nectar source for a variety of creatures......

Tiny weevils pollinating a Field Thistle
Native bees like Bumble Bees, Digger Bees and Leaf-Cutter bees rely on the Field thistle for nectar before the cold sets in.

Many species of butterfly, especially Great Spangled Fritillaries, flock to the fluffy blooms to feed.

Ruby-Throated Hummingbirds enjoy thistle flowers, too.

Thistle seed is a major fall and winter food source for the American Goldfinch, as well as Purple Finches, Pine Siskins, Indigo Buntings and Carolina Chickadees.

Goldfinches and thistles were made to compliment one another!
Goldfinches love their thistles so much, they even use the seed down to line their nests with, once they've eaten their fill of seeds, of course.

The prickly Field Thistle may not be the most inviting wildflower, but they are indispensable, beautiful and downright admirable for their impressive defenses. 

As you step outdoors on these first bright, mild days and take a stroll under the azure autumn sky, give a nod to the Field Thistle, and all of the creatures flocking to it.

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

Click here to read about last week's wildflower, Common Sneezeweed

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 - Jack Carman

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

Forest Plants of the Southeast and their Wildlife Uses - James H. Miller & Karl V. Miller

Identifying & Harvesting Edible and Medicinal Plants in Wild (and Not So Wild) Places - "Wildman" Steve Brill

1 comment:

  1. I did not know that artichokes are a thistle! That is way too cool! Thanks for sharing.

    Thanks for linking up with Green Thumb Thursday. We hope to see you again this week!