Yellow dock is one of those most common looking weeds which almost everyone has in their yard. If not in the yard then it will probably be close by in the ditch. It loves to grow in rich disturbed soil in the garden. There are several species including the sheep sorrel (Rumex acetosella). Sheep sorrel is quite a bit different from the Crispus and rudra, as it doesn’t have the root system of the others. The tops of the sheep sorrel are the most used in that particular plant whereas the root is the part used in yellow dock. The leaves of yellow dock are lanceolate, acute, strongly undulated, and crisped at the edges, of a light-green color; radical ones on long petioles, truncate, or subcordate at base; uppermost narrower, and nearly sessile. They are easy to recognize in the fall because they will develop a red marking that is due to the effect of the cold weather or so it appears. In the late fall the flowering stems come up and are green and the flowers look more like seeds and quickly make the transition. Then, they quickly turn brown, and the plant becomes quite obvious in mass because of its brown seed heads standing above the surrounding grasses. This is the best time of year to harvest after the seed heads have turned brown. The roots are spindle shaped and sometimes are about 2 or three inches thick at the top and branch very quickly sometimes into several roots which is how the plant multiples also.
Yellow Dock | Blue Boy Herbs - geckosart.com, http://geckosart.com/blueboyherbs/index.php/botanical-descriptions/yellow-dock/ (accessed January 19, 2017).