While yellow dock may not be the first weed that comes to mind for many home gardeners, it is essential to keep an eye out for it. Yellow dock is a tall perennial plant characterized by its long, sword-like leaves that have wavy edges. Its seed head is noticeable even during the winter months. This plant is found throughout the United States and has significant invasive potential due to the enormous number of seeds it produces and the long duration they remain viable in the soil—sometimes for decades! Therefore, it is crucial to remove yellow dock from your yard as soon as you notice it. Many weeds can be obscure and easy to overlook, but yellow dock is distinctive, making it relatively simple to identify.
Yellow dock is mildly toxic to humans and can be harmful to pets.
| Common Name | Yellow dock, curly dock, narrowleaf dock, sour dock |
| Botanical Name | Rumex crispus |
| Plant Type | Perennial, herbaceous |
| Mature Size | 18-48 in. tall |
| Soil Type | Moist |
| Bloom Time | Summer |
| Flower Color | Green |
| Hardiness Zones | 4-8 (USDA) |
| Native Area | Europe, Asia, Africa |
| Toxicity | Toxic to humans, toxic to pets |
Invasiveness of Yellow Dock
Warning
Yellow dock has become naturalized in many parts of the world. In certain states in the United States, such as California and Oregon, yellow dock is classified as an invasive plant.
Although the plant is commonly listed as hardy in USDA zones 4 through 8, it can be found almost anywhere in the United States, even in warmer climates and in Alaska. This widespread presence is not surprising, as yellow dock is originally from Africa, temperate and tropical Asia, and Europe.
Yellow dock is known to tolerate poor, disturbed soils, but it thrives best in rich, loamy soils with full sunlight and sufficient water. It often grows in overly wet soils or areas with standing water, such as irrigation ditches. You can also find it along roadsides, in wastelands, on cultivated farmland, and in pastures. This is a significant concern because yellow dock is not only toxic to pets but also harmful to livestock like cattle and sheep.
Each yellow dock plant can produce between 40,000 and 60,000 seeds, depending on various factors, and these seeds are dispersed from late summer through winter. This staggering number of seeds, combined with their remarkable viability—seeds can survive in undisturbed soil for over 50 years—makes yellow dock a formidable invader. When yellow dock spreads, it can choke out crops and native plants, depriving them of essential nutrients, sunlight, and space.
Another issue with yellow dock is that it serves as an alternate host for various crop diseases caused by viruses, fungi, and nematodes.
What Does Yellow Dock Look Like?
Yellow dock is part of the buckwheat family, which is recognized by the nodes that appear along the plant’s stems. Young seedlings can be entirely green or may take on a reddish hue during cooler months. Mature plants display dark green or bluish-green leaves. The lower leaves are quite long, measuring between 6 to 12 inches in length. Pay special attention to the sword-like shape and the curled or wavy edges of the leaves. As the leaves mature, they may develop a reddish-purple tint.
The unique flower head of the plant, which remains after the blooms have dried and turned reddish-brown, is a helpful feature for identifying yellow dock. The flowers initially appear in a less distinctive light green color (sometimes with a reddish tinge). They bloom in clusters, forming multiple long, slender flower stalks at the top of the plant.
Another characteristic that aids in identifying yellow dock is its height. The plant can grow up to 4 feet tall when fully mature.
The stems of yellow dock are fleshy and smooth, often exhibiting a reddish color, and they die back in the fall. The plant has a large, deep taproot that is yellowish-orange in color.
The Spruce / Evgeniya Vlasova
The Spruce / Evgeniya Vlasova
The Spruce / Evgeniya Vlasova
How to Get Rid of Yellow Dock
If the plant is still small, you can easily dig it out using a shovel or a spade. Hand-pulling is not recommended because the long taproot may break, allowing the plant to regrow from any remaining root segments.
Removing mature yellow dock plants along with their entire taproot can be quite challenging. Instead of attempting to dig it out, you can repeatedly cut any vegetative growth starting in the spring. This method helps to gradually deplete 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 completely eliminate it. If you are dealing with a large area infested with yellow dock, mowing it repeatedly can weaken the plant significantly.
Yellow dock struggles to thrive when competing against other vigorously growing plants. Therefore, after you remove it, it is essential to promptly replant the area. Given the vast number of yellow dock seeds and their long viability, there will likely still be seeds remaining in the soil. However, the presence of other plants or crops will reduce the chances of yellow dock reemerging.
How to Prevent Yellow Dock from Spreading
The most important step you can take to prevent yellow dock from spreading is to cut it down before it begins its long flowering period, which lasts from June to September.
How to Tell the Difference Between Yellow and Broadleaf Dock
Broadleaf dock (Rumex obtusifolius) is a related weed that can also grow up to 4 feet tall. Distinguishing between the two is quite straightforward: true to its name, broadleaf dock has basal leaves that are very wide (about 4 inches across), while yellow dock’s basal leaves are much narrower (around 1 inch across). The basal leaves of broadleaf dock are shaped more like shields, whereas yellow dock’s leaves are shaped like swords.
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Are curly dock and yellow dock the same thing?
Yes, curly dock and yellow dock are two different common names for the same plant, Rumex crispus.
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Is yellow dock edible?
While the plant is technically edible, it is generally considered too bitter to be enjoyable.
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When did yellow dock come to the United States?
While the exact date is unknown, yellow dock has been present on the North American continent since colonial times, with the first sightings dating back to the 1700s.
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What are the most common types of dock plants?
The most common members of the Rumex genus include two edible plants: sorrel (R. acetosa) and bloody dock, also known as red-veined sorrel (R. sanguineus), as well as the weed broadleaf or bitter dock (R. obtusifolius).