TC3 Farm Plant Identification Tour – Student Post

A Plant Identification Tour of the TC3 Farm – Learning Common “Weeds” – Student Post by Make

Today’s post is a plant identification tour of the TC3 Farm. All the species we will discuss today are potentially “weeds” on the farm. But what is a weed? A weed is simply a plant that is growing where it is not wanted (even a single tomato plant growing in a field of squash can be identified as a weed). The plants being discussed here are all things that grow on the TC3 Farm and can sometimes be found where we don’t want them. Gardeners and farmers alike know all too well the main problem with weeds: competition with their cultivated crops which reduces yields.

Here are some things to think about as you learn to identify your weeds. There are other attributes weeds possess that often get ignored. Weeds can be used for sustenance as mentioned in an earlier post ( Weeds can be medicinal and are used in traditional medicine. Specific weeds under certain conditions can be used productively in a sustainable manner to properly manage your soil and environment (add organic matter, habitat for beneficial insects, encourage healthy soil biota). Other weeds need to be suppressed because they can harbor certain pests and ultimately leave you open to crop failures.


The first weed in our plant identification tour is known by the common name Horsenettle (Solanum carolinense). It is an herbaceous perennial flowering plant that belongs to the Solanaceae or Nightshade family. All parts of the plant are toxic to human health when ingested and can lead to death (its fruit which can resemble tomatoes are the most toxic). The most identifiable characteristic are its spines on the stem and underside of its larger leaves. Each fruit contains around 60 seeds. It flowers throughout the summer, from April to October. The plant can spread through seed and rhizomes (sexually and vegetatively). This plant can harbor and sustain Colorado Potato Beetles (Leptinotarsa decemlineata), Eggplant Flea Beetle (Epitrix fuscula), and Tobacco Hornworm (Manduca sexta) just to mention a few. Leaving the Horsenettle unchecked can lead to lower crop yields for Potatoes, Tomatoes, and Eggplants. Hint: The plant should be removed preferably with gloves as to avoid the stinging spines which can become embedded in your skin.

Buttercup Flower

Our next plant has a delicate beauty of sorts and is known commonly as the Buttercup (Ranunculus species). This plant belongs to the Ranunculaceae family and most are perennial. The plant is easily identifiable by its yellow (some varieties are white) flowers which usually have five petals and sepals with numerous stamens and pistils. This plant is more likely to grow in wet areas and can grow in some standing water. This plant is toxic to cattle, horses, and other livestock and is usually eaten by animals if there isn’t anything else around. The toxic substances in it decay through drying so hay with dried buttercup is safe for animal consumption. There are some medicinal uses for individuals using traditional medicine to treat rheumatism or fever. Unlike our last weed this plant can be beneficial in respect to insects and your entire ecosystem. Specifically it can be a food source for insects in the Order Lepidoptera (Butterflies and Moths) that are pollinators and beneficial for fruit development of cash crops.

Lanbsquarters growing in lettuce bed.

Lambsquarters (Chenopodium album) is a common weed that has many uses, and in some parts of the world (mainly India) is used as a main source of food for humans and animals alike. It is a member of the Amaranthaceae family. The leaves are alternate and varied in appearance. The first leaves, near the base of the plant, are toothed and roughly diamond-shaped. The leaves on the upper part of the flowering stems are entire and lanceolate in appearance, with a whitish coat on the underside. It is one of the main competitive weeds in the TC3 Farm fields. It is attractive to leaf miners which are insect pests, and can thus work as a trap crop when used in a companion planting method. This means that Lambsquarters will act as host for the pests that is more attractive to them than the cash crop.

Cinquefoil on the TC3 Farm

Potentilla, otherwise known commonly as Cinquefoil, include over 300 species of annual, biennial, and perennial herbaceous flowering plants belonging to the Rose (Rosaceae) family. The leaves of the plant can come in pinnate or palmate with 5 leaflets such as the ones found on the TC3 farm. The flowers are usually yellow but can be red, pinkish, or white as we see here. The fruits may be strawberry-like but are inedible. There are many medicinal uses and superstitious beliefs attached to the plant. It was used as an ingredient for love potions, to scare off witches, and increase a fisherman’s catch. In medieval times, it was a sought-after device to paint on a knight’s shield who had achieved mastery over the self. Cinquefoils can provide food for pollinators, thus allowing the opportunity to attract and sustain these beneficial insects (specifically bees, hoverflies, and butterflies just to mention a few) on the farm.


The next weed on our plant identification tour is Mugwort. Mugwort is the common name for many species of the genus Artemisia and is part of the Asteraceae family. It is an herb that has generalist insecticidal (good at eliminating a wide range of insects) and allelopathic (naturally produces chemicals which can inhibit/encouage the growth of surrounding plants) properties. In this case Mugwort can and will slow production down in surrounding plants by not only competing for the same nutrients/resources but by producing chemicals which stop plants from growing (a toxin). Mugwort is widely used in Asiatic cultures for traditional medicine but more commonly as a staple ingredient in some food dishes. Mugwort pollen is believed to be one of the main sources of hay fever in which the highest concentration is usually found between 9 and 11 am. Pregnant women must never be in contact or ingest the plant due to its properties in relaxing the uterus and easing menstruation.




Sweet White Clover

Sweet white clover (Melilotus albus), is a legume, and thus is part of the pea (Fabaceae) family. It is a biennial herbaceous plant which can grow up to 5 ft. in height and its leaves are alternate, divided into three finely toothed leaflets, middle leaflet grows on a short stalk. It was introduced to the United States as a forage crop for cattle, but has since become a problematic weed and is an aggressive colonizer of disturbed areas. It can serve as a food source for bees, and its nitrogen fixing ability can be useful. Its seeds remain viable in the soil for 30 years, and can float through air or disperse in water. This has made the plant an invasive species which has spread all throughout North America.

St. John's Wort
St. John’s Wort in Flower at the TC3 Farm

The last “weed” on our plant identification tour is the common St. John’s Wort, scientifically known as Hypericum perforatum, which is an herbaceous perennial plant in the family Hypericaceae. The plant can proliferate through its rhizomes or seeds (seeds can remain viable for decades) and its leaves are stalk-less and opposite. The leaves are a yellowish green with dots of transparent glandular spots. If one takes the leaves and places them into a light source one can see the perforations within the leaves. The flowers have five petals and numerous stamens which are bundled at its base. Ingestion by livestock such as horses, sheep, and cattle (and humans) can cause photosensitization (sensitivity to ultra-violet light and phototoxic reaction to skin [sunburn]), central nervous system depression, spontaneous abortion, or death. Lastly, this plant is well known to help individuals suffering from mild to moderate depression. The use of St. John’s Wort as an herbal remedy is popular in the U.S.  because it doesn’t induce many of the common side effects of prescribed anti-depressants such as nausea, weight gain and loss of sex drive.

There are various methods used for weed suppression which include pulling by hand, using hand tools like the scuffle hoe or a flame weeder, and in large scale production tools like the Spring Tooth Harrow/Field Cultivator can be used (references contain links to items in bold). Certain weeds can sometimes be left to grow right up until the point before flowering and seeds develop, on an area planned to be left fallow, and then tilled in. This practice helps the environment and your soil overall and it’s sustainable.

If you want to learn more or are asking about that one weed in your field/plot, you can find weeds not mentioned in this guide by obtaining one entire (roots and all) sample plant and using a weed identification guide like or

Warning to all readers: please do not use the information from this post to replace sound medical advice or treatment(s) from an actual medical professional. Use caution when selecting plants to eat by using several quality sources and proper identification.




Cinquefoil, Brittanica,

Colorado Potato Beetle,

Department of Natural Resources, White and yellow sweetclover (Melitotus alba, M. officinalis),

Field Cultivator,

Flame Weeder,


Hypericum perforatum,

Isolation and characterization of allelopathic volatiles from mugwort (Artemisia vulgaris)



MUGWORT: Uses, Side Effects, Interactions and Warnings – WebMD

Photosensitization in Horses,



Scuffle Hoe,

Solanum Carolinense,

Spring Tooth Harrow,

St. John’s Wort, University of Maryland Medical Center,

Sweet White Clover, Melilotus albus,

University of Wisconsin, Weed Identification and Management,

University of Missouri, Weed Id Guide,

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