Some plants are so common we cannot help but take them for granted. Sow thistle definitely falls into this category.
Anyone with a decent stretch of field, or even a big lawn, is bound to have sow thistle growing somewhere in it.
If you’ve just scoffed at it or attempted to root it out as a weed, you’ve really missed out; sow thistle is a great edible pant in its own right.
Here is what you need to know about foraging and eating sow thistle.
What is Sow Thistle?
Sow thistle is an edible plant that is native to Europe and Asia.
However, sow thistle can be found in most temperate regions, including the lower Eastern side of the United States.
Able to grow in a variety of habitats, including pavement, garden borders, and different soil textures, sow thistle is easily found, yet can be tricky to identify.
Sow thistle is preferred by cattle, deer, and smaller animals, including rabbits, and there are plenty of reasons as to why.
This recognizable plant, most commonly known as an invasive weed, can be spotted throughout the countryside and cityscapes, but it is important to avoid foraging sow thistle in heavily trafficked areas.
Keep the forest creatures in mind when you forage this beneficial, bitter plant, and keep reading to learn about why this broad leaf plant is worth foraging.
How to Identify Sow Thistle
Sow thistle, also known by its botanical name Sonchus arvensis glabrescens, is a perennial plant that grows in clumps and in most environments.
The genus, Sonchus, notes the daisy family that sow thistle is a part of, and is commonly confused with its plant cousin, the dandelion.
In this family, there are various types of thistles, yet they are true thistle varieties.
“True” thistle plants are almost impossible to harvest without risking cutting yourself, as thistle plants have sharp prickers or thorns growing out of the stems and leaves.
Other names that perennial sow thistle is known by include corn sow thistle, field milk thistle, milk thistle, gutweed, and dindle.
It is important to note that while sow thistle may be referred to as milk thistle, milk thistle is visually different from sow thistle and is harvested and used for different reasons.
Genuine milk thistle is identifiable by the plant’s purple blossom that is more rounded or spherical than the sow thistle flowers.
In identification books and on plant identification websites, milk thistle is known by its botanical name, Silybum marianum.
So, if you are looking for sow thistle, do not purchase or harvest milk thistle in its place.
Sow thistle propagates through the seeds and roots, and can grow up to be around three feet in height. Thistle varieties are known for their unique, prickly texture that can be identified in the leaves on sow thistle.
The stems of common, perennial sow thistle do not have the fibrous texture, however.
The leaves are often wavy or lobed, prickly, and reach dimensions ranging between three to 13 inches in length, and between one to five inches in width.
Besides the prickly leaves, sow thistle also has flowers that are easy to identify. Similar to dandelion flowers, sow thistle flowers are small and yellow, reaching a tiny size of less than one inch.
These flowers grow in small clusters on the thistle plant, each with their own set of short, white hairs that sparsely cover the exterior of the flower before it blooms.
Once the flowers are past their flowering stage, then comes the moment where sow thistle resembles dandelions, as the yellow flower petals will be replaced with white, puffy seeds that will float away with the wind, which will plant future propagations of the plant.
Most thistle varieties have lobed leaves, meaning there are gaps between the “teeth” of the leaves.
Sow thistle leaves can also be described as soft, or leathery, because their leaves are not as prickly to the touch as the spiny sow thistle, or genuine thistle plants, which have thorns.
The early leaves differ slightly from the mature leaves, as the fresh, young leaves will have the same hairs as the flowers have.
Then, when the leaves mature, sow thistle leaves are smooth and thin, developing more distinctive lobed sections as the plant grows.
Throughout each part of sow thistle, you can find a milky sap within the leaves and stems.
More specifically, the sap is found within the plant walls of the stems, as the stems of thistle plants are hollow.
As easy way to remember this tip in identification is that the genus name, Sonchus, derives from the meaning “hollow” in Greek, to signify the empty space in the stalks.
Similar Plants to Sow Thistle (Look-alikes)
Other plants that are often confused for sow thistle, and vice versa:
- the well-known dandelion,
- annual sow thistle,
- prickly sow thistle,
- and prickly lettuce.
Two of these four plants do share many characteristics of the perennial sow thistle, as they are both part of the Sonchus family, yet have subtle differences to double check before foraging.
To help in identifying the correct sow thistle plant, let’s take a look at the most similar plants.
Annual sow thistle is one of the thistle plants with the most subtle differences, the most notable being that this type of sow thistle does not regrow year after year.
The botanical name makes note of this difference, as annual sow thistle is called Sonchus oleraceus.
Both annual and perennial sow thistle are edible, but the key to telling the two plants apart is texture and flowers.
Annual sow thistle has smaller flowers, and the foliage tends to be less prickly, yet the leaves can have more noticeable lobes in the annual version.
The annual sow thistle plant does not have the extensive root system that perennial sow thistle does, and also does not start to emerge as early as the perennial version.
At the end of the day, annual sow thistle’s appearance is nearly the same as perennial sow thistle.
Another type of thistle that is often confused for standard sow thistle is the prickly sow thistle plant.
When identifying prickly sow thistle, its botanical name is Spiny Sonchus asper, which deviates from the standard genus name first basis.
The root system is simpler when compared to the other varieties, as spiny sow thistle has a taproot system, which is a singular root.
The leaves have “teeth”, or a rougher edge that has a notable prickly texture when touched. Spiny sow thistle blooms around the same time that common sow thistle does, with yellow flowers in small clusters.
However, spiny sow thistle has leaves that often are a darker shade of green, with purple margins lining the outer side of the leaves.
While sow thistle plants can develop purplish markings as they age, spiny sow thistle is identifiable with this feature earlier on.
The mature texture of spiny sow thistle is more rugged than the other two variants, as the leaves of the spiny variety have been described as waxy, with a shine that also compliments this description.
The early stages of the spiny sow thistle are more easily distinguishable from perennial type, as the leaves will start by creating a base, rounding inwards to create a lobed foundation.
This base will continue to grow around the stem of the plant. Lastly, spiny sow thistle is also an annual variety of its plant family.
Prickly lettuce, also known as Lactuca serriola, is not a part of the Sonchus family, but shares the notable yellow flower characteristic.
Also known as China lettuce or compass plant, this plant looks similar to dandelions, has the staple milk-like sap inside the plants parts, and also has the deep root system that sow thistle has.
However, this plant blooms in early spring to mid-summer, where sow thistle flowers later in the year.
Prickly lettuce is a biennial plant that originates from Asia and Europe, similar to sow thistle plants, with thistle prickers that are not sharp enough to harm those who harvest it.
Similar to spiny sow thistle, prickly lettuce is waxy, yet can sometimes have red markings on the leaves.
Prickly lettuce becomes more bitter as it ages, so it is best consumed young, yet should only be consumed in small quantities.
Dandelions are quite similar in appearance to sow thistle with a quick glance, but when you compare the two, the key difference is the flower count. Dandelions, or Taraxacum officinale, only have one flower per stalk, whereas sow thistle has multiple small flowers per stalk.
Similar to dandelions, sow thistle is also a great source of nectar and pollen for pollinators, including butterflies and bees.
Dandelions are actually more bitter than sow thistle, yet are equally great as a source of nutrients or as a coffee alternative.
The leaves of the dandelion look spikier than sow thistle leaves, with roots that makes dandelion easier to remove.
For what dandelions can be used for, health benefit wise, sow thistle can be used in its place.
The first key in foraging quality sow thistle is to harvest the plant young, before it reaches the flowering stage, which takes place during the summer and fall seasons, between June to October.
This is important because sow thistle, as with most other varieties of thistle, is a bitter plant. The longer sow thistle grows, and once the flowers fully bloom, the more bitter the taste becomes.
This bitterness is a result of the white sap inside the plant, which is normally an indication to not consume the plant. However, sow thistle is one of the few exceptions to this foraging guideline.
While the stalks are edible, and a great source of the plant’s sap, the stems will reach a point where they are inedible due to being too stiff, even after being cooked.
For the benefit of the consumer, it is recommended to separate the leaves from the stalks and leaf spines.
Whether you forage annual or perennial sow thistle, both versions produce several thousands worth of seeds that naturally propagate the next generation of sow thistle plants.
This makes sow thistle incredibly invasive, yet easily grown as one plant, on average, produces over 200,000 seeds.
Foraging the seeds and propagating sow thistle in your yard can be beneficial, if maintained properly, as to prevent the sow thistle plants from overrunning gardens and yards.
The sow thistle is beneficial in keeping biological balance in gardens, as the plants will attract insects and creatures that can become pests.
Such insects, such as ladybugs and beetles, and animals like deer will be attracted to the sow thistle, versus immediately approaching your steadily growing crops.
Sow thistle is difficult to rid of, as most thistle of the true and false kinds have weed killers specifically produced for them.
In the case of harvesting the entire plant, the roots of sow thistle grow several inches into the soil.
The roots of this plant often grow horizontally, which can make it easier to pull the plant up but can be tricky with the numerous smaller roots that grow from the main roots.
With most gardening and foraging, it is easiest to gently dig around the plant, and pry the roots from the soil, when the soil is mostly dry and when it is earlier in the day.
Foraging in the early morning is key to keeping as many nutrients in the plant as possible, as when the morning dew begins to dry and the plant is greeted with sunlight, the dried water will mildly heat the plant, which can cause nutrient loss.
How to Use Sow Thistle
The parts that are usable from the sow thistle plant include the leaves, flowers, and roots. Sow thistle is a great plant to have on hand if you keep rabbits or pigs at home.
Giving sow thistle to nursing cattle was part of the reason that the plant is known as “sow” thistle today, as farmers once believed that the sap would increase milk production in nursing cows.
Sow thistle, when consumed, can be a good source for vitamins A and C, with traces of mineral salts found in the leaves.
The leaves are the most vitamin and mineral packed, as the leaves also contain traces of thiamine, riboflavin, calcium, phosphorus, and niacin.
Sow thistle also provides a source of antioxidants and biotic compounds, which are compounds that can help prevent the development of HIV and other diseases.
The other form of compounds found in the plant, known as cytotoxic compounds, are effective in the prevention of cancer, as they attack and prevent cancer cells from forming.
Sow thistle has shown to contain anti-inflammatory and anti-thigmotactic properties, which aid in the relief of inflammation-based pain, such as muscle aches, and in easing anxiety and overactive locomotor activity.
On a more specific note, about the plant parts, the sow thistle leaves have shown to contain sedative and diuretic effects, which provide a feeling of relaxation, while helping in the production of natural urine flow.
Used externally, the sap has been prepared and used for earaches, The sap is used a gentle cleanser, as it can help draw out excess ear wax to ease the ache.
The best ways to use the sow thistle plant is to mix the leaves into salads. Cooking sow thistle is often saved for last if the parts were harvested closer to the flowering stage.
However, cooking sow thistle down to remove the slightly bitter flavor can allow more versatility in using sow thistle in culinary ways.
The root is often saved for roasting, when harvested young as well, and can be ground up to become a coffee alternative.
This is most likely due to sow thistle’s connection to dandelion, which is also roasted, ground, and brewed in place of coffee.
If you’d like to have a real treat cooking this plant, try making buttered sow thistle tips as an elegant, healthy side dish.
Although the sap has been used as a gum in different cultures around the world, the sap is generally not the part you want to consume.
Rather, the sap can be saved and used externally, as it has been used to remove warts; however, it is simply best to stick to using the leaves, flowers, and roots.
Amongst the other types of sow thistle, mainly the spiny and annual varieties, there are no differing uses for either type.
The best course of action before substituting other varieties in place of the common perennial sow thistle is to fact check and research other people’s experiences in using other forms of sow thistle.
If you are not interested in consuming the sow thistle parts, and have livestock, sow thistle plants are great to plant where cattle and other farm animals roam.
The nutritional composition of sow thistle shouldn’t be squandered and can easily by planted sporadically with the numerous seeds that the plants release every year.
So, sow thistle makes great fodder for cattle, keeping them stocked up on their vitamins A and C, while offering a natural snack throughout the day.
While sow thistle is a beneficial plant in many ways, there are a few precautions to take note of before foraging and consuming the lettuce look alike.
Sow thistle is rich in oxalic acid, which is a compound that is most commonly found in plant life that can contribute to the formation of kidney stones in the human body.
If you or someone else who would be consuming sow thistle has previous history with kidney stones, or has medical history with other kidney health concerns, it is recommended to avoid using sow thistle.
Sow Thistle: Worth a Second Look
Don’t let that sow thistle growing in your fallow field go to waste.
This is a terrific plant to make the most of during the summer, by turning it into a go-to salad green, or delicious side dish.
So, once you can confidently identify this tasty plant, start putting it to use on your homestead right away.
When Tom Harkins is not busy doing emergency repairs to his 200 year-old New England home, he tries to send all of his time gardening, home brewing, foraging, and taking care of his ever-growing flock of chickens, turkey and geese.