Yellow Dock Plants

Yellow dock plants with long, red, skinny flower stalk clusters next to white and yellow wildflowers

The Spruce / Evgeniya Vlasova

Many weeds are obscure plants that are easy to miss, but yellow dock is a weed that stands out. It is easy to identify, and the reasons for bothering to identify it include that it is:

  • Medicinal
  • Edible
  • Poisonous
  • Invasive

Botanical Classification for Yellow Dock Plants

Plant taxonomy classifies yellow dock as Rumex crispus. It is considered a broadleaf, perennial "weed," "wildflower," or "herb," depending on your perspective. This curious plant belongs to the buckwheat family, which is identified by the nodes that punctuate the plants' stems (an even clearer example being those found on Japanese knotweed). It is in the same genus as another weed commonly found in North America, sheep sorrel (Rumex acetosella).

Yellow Dock Plant Identification

The distinct flower head of the plant that remains after the blooms have dried and turned brown is helpful for the identification of yellow dock. The flowers start out a much less distinctive light-greenish color (they can have a reddish tinge, too). Blooming occurs in clusters in the form of multiple, long, skinny flower stalks at the top of the plant.

The plant's dark green leaves will further help you identify it when you find it. The bottom leaves can be quite long, ranging from 1/2 foot to 1 foot in length. Look, in particular, for the sword-like shape and the curled edges of the foliage. It is from this curly leaf margin that the weed gets the nickname of "curly dock." This alternate common name is also sometimes given as "curled dock"; the species name, crispus is Latin for "curly."

Another aid in identifying this weed is its height. The plant reaches as much as 4 feet tall at maturity. A related weed can also grow to be as much as 4 feet tall: bitter, or "broadleaf" dock (Rumex obtusifolius). But it is easy to tell the two apart: True to its name, the broadleaf type has bottom, or "basal" leaves that are very wide (4 inches across, versus 1 inch across for yellow dock plants). Whereas the subject of this article has basal leaves shaped like swords, the basal leaves of its relative are shaped more like shields.

Indigenous to Europe, Rumex crispus has become naturalized across much of the world. It often tolerates poor, disturbed soils and is frequently found along roadsides, although it prefers to grow in rich, loamy soils in full sun and with adequate water. In some states of the U.S., yellow dock is considered an invasive plant.

Yellow dock plant with multiple flower stalk clusters with small yellow petals in sunlight

The Spruce / Evgeniya Vlasova

Yellow dock plants with tall skinny flower stalks in sunlight

The Spruce / Evgeniya Vlasova

Yellow dock plants with red tinged flower stalks next to tall white and yellow wildflowers near dirt pathway

The Spruce / Evgeniya Vlasova

Weed Control

Rumex crispus produces a long taproot. If you are going to try to dig it out, you must dig deep, so as to remove the whole root; otherwise, as a perennial weed, the plant will re-emerge. Those of you aware of the challenges involved in dandelion control will understand this problem.

Despite its medicinal qualities, Rumex crispus is listed as a plant poisonous to dogs by the ASPCA. Its toxicity is due to its oxalic acid content. For the same reason, while the leaves are edible, it is best to avoid eating them in large quantities. They can be eaten either raw (when young and tender) or steamed.

Home Remedy Against Rash From Stinging Nettles

If your skin has ever brushed up against stinging nettles (Urtica dioica) while you were working in the garden, you know about the burning sensation caused by their spines, followed by an itchy rash. Fortunately, Rumex crispus, a home remedy for such skin irritation, often grows near stinging nettle. Just roll a leaf of yellow dock between your thumb and forefinger to crush it, then doctor your wound with the juicy pulp left over, and the burning will subside.

Yellow dock has, in fact, been used medicinally (for a number of ailments) for ages, which is why many prefer to refer to it as an "herb." But it is mainly the plant's root, rather than its leaves, that has been used in folk medicine. In fact, the common name, "yellow dock" refers to the yellowish color often found inside the root, when it is sliced open.

The yellowish root notwithstanding, the signature color of Rumex crispus, in the eyes of many students of wild plants, is brown. That is the color of the dried flower-head in fall. Once you are able to use this feature to identify it as yellow dock, you will never forget this plant.

You have to love the texture of this dried flower spike: If you grab the coarse brown spike and slide your hand along it, you will come away with a handful of small, crispy flakes (the seeds and dried sepals). They make you think of coffee grounds, which is appropriate since people have roasted this plant's seeds for use as a coffee substitute in the past.