Yellow dock is mildly toxic to humans and toxic to pets. Yellow dock often tolerates poor, disturbed soils although it prefers to grow in rich, loamy soils in full sun and with adequate water. It often grows in overwatered soils or areas of standing water and in irrigation ditches. It is equally found along roadsides and in wasteland, on cultivated farmland, and in pastures, creating a problem because yellow dock is not only toxic to pets but also toxic to cattle and sheep. Each plant produces between 40,000 and 60,000 seeds depending on the source, and they are dispersed from late summer through the winter. This huge number of seeds is combined with their extreme viability—seeds can survive in undisturbed soil for more than 50 years. Where yellow dock spreads, it chokes out crops and native plants, depriving them of nutrients, sunlight, and space. Another problem of yellow dock is that the plant is an alternate host for several crop diseases caused by viruses, fungi, and nematodes.
What Does Yellow Dock Look Like?
Yellow dock belongs to the buckwheat family, which is identified by the nodes that punctuate the plant’s stems. Young seedlings are either entirely green or take a red tinge in cooler months. Mature plants have dark green leaves or bluish-green leaves. 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 or wavy edges of the foliage. As the leaves age, they become reddish-purple. The distinct flower head of the plant that remains after the blooms have dried and turned reddish-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. Another aid in identifying the plant is its height. The plant reaches as much as 4 feet tall at maturity. The fleshy, smooth stems with a reddish color die back in the fall. Yellow dock has a large, deep taproot that is yellowish-orange in color.
How to Get Rid of Yellow Dock
As long as the plant is small, you can dig it out with a shovel or a spade. Hand-pulling is not a good option because the long taproot will likely rip and the plant regrows from any root segments. Removing mature plants with their entire tap root is challenging. Instead of trying to dig it out, cut any vegetative growth repeatedly starting in the spring in order to gradually exhaust the plant’s energy reserves. Once the plant is weakened, it will still need to be treated with an herbicide such as glyphosate, clopyralid, triclopyr, or 2,4-D to eradicate it. If you are dealing with a large infested area, you can also mow it repeatedly. Yellow dock does not do well when it has to compete against other vigorously growing plants so after you remove it, replant the area promptly. Given the large number of seeds of yellow dock and their long viability, there will likely still be seeds in the soil but the presence of other plants or crops will make the reemergence of yellow dock less likely.
How to Prevent Yellow Dock from Spreading
Cutting down yellow dock before it starts its long flowering period, which can stretch from June into September, is the most important thing you can do to prevent its spread.
