What is Dock?
The genus Rumex can be broadly divided into two groups of wild edible plants: the docks and the sorrels. Both are delicious, but this article is about docks, primarily Rumex crispus (curly dock) and R. obtusifolius (broad-leaved dock). The sorrels will get their own article very soon, I promise.
Docks were popular wild edibles during the Depression due to their tart, lemony flavor, their widespread abundance, and the fact that they were free for the taking.
Today most people have forgotten about this common and tasty edible weed, but I gather enough every spring to blanch, freeze, and enjoy all year long.
Docks are perennial plants growing from taproots and they are most often found in neglected, disturbed ground like open fields and along roadsides. While docks may be happiest and tastiest when they grow with plenty of moisture, the taproot indicates they are drought tolerant plants. Docks grow as basal rosettes of foliage in early spring; they are often one of the first greens to emerge. By late spring or early summer, dock produces tall flower stalks that bear copious amounts of seed, which are also edible. The seed, however, can be labor intensive to process and reports on its palatability are highly varied. I'm not convinced it's worth the trouble unless you're in a survival situation and desperately need to make flour. Let's hope that never happens to you.
The foliage of mature dock plants may be from 1-3 feet tall, depending on growing conditions, but in early spring, when it's at its most delicious, the smaller plants may be hard to spot. Look for the tall, dark brown, branched flower stalks that produced the prior year's seed crop.These often remain standing over winter and new growth will emerge from the base of the stalk.
Which Docks are Edible?
There are many edible docks, but curly dock and broad-leaved dock are the most common in the USA and Europe. Other edible docks include R. occidentalis (western dock), R. longifolius (yard dock), and R. stenphyllus (field dock). R. hymenosepalus (wild rhubarb) is common in the desert Southwest and is larger and more succulent than many other docks.It has been a traditional food and dye source for several Native American tribes.
Patience dock (R. patientia) was once cultivated as a vegetable in both the USA and Europe and is still grown as such by a small number of gardeners. If you read about a green called Patience, you're reading about patience dock. Patience dock may be found as a feral plant, if you're lucky. It's larger, more tender, and perhaps more delicious than any other dock plant. You can find seeds for sale on line.
One of the best identification features for docks is the thin sheath that covers the nodes where leaves emerge.This is called the ocrea, and it turns brown as the plant ages. The condition of the ocrea may be a good indicator of how tender and tasty that dock plant is. A second excellent identification feature is the mucilaginous quality of the stems.
If you pick what you think is a young dock leaf but your hand isn't covered with mucilage, you have not picked a young dock leaf.
The sour flavor of dock comes from oxalic acid, which, when consumed in large quantities, may cause kidney stones. The same compound is found in spinach. If your doctor has advised you not to eat spinach or if you are prone to kidney stones, don't eat dock. If you are generally healthy and don't gorge yourself on multiple pounds of dock every day for a month, you should be fine. If you are nervous about this, err on the side of caution.
Curly dock may also be called yellow dock, sour dock, or narrowleaf dock, depending on where you live. Common names are tricky for that very reason; they change from place to place. If you need to know precisely and with absolute certainty which plant you're dealing with, use the botanical Latin name.
End of speech.
The leaf shape of curly dock is highly variable, both on a single plant and from plant to plant. Younger plants tend to have foliage with less curly leaf margins. Also, their leaves may be slightly rounder and broader than those of mature curly dock plants. Mature foliage is generally narrow (almost linear), smooth, with very wavy leaf margins.
The root of curly dock is yellow and intensely bitter. While it has traditionally been used for medicinal purposes, I prefer to use it in cocktail bitters.
Broad-leaved dock is similar to curly dock in its growth habit (taproot, smooth leaf surface, mucilaginous) but its leaves lack the highly wavy margin of curly dock. Mature broad-leaved dock leaves may have a slight wave to them, but not the serious undulation of curly dock. Additionally, broad-leaved dock foliage is wider and more elliptical in shape than curly dock leaves.
Broad-leaved dock is sometimes called bitter dock and while it's true that mature leaves may be bitter, don't forget that bitter leaves are some of our favorite greens. Arugula, dandelion, collards, and spinach are all considered bitter greens and when cooked, they combine well with mild greens.
How & When to Harvest Dock
Both curly and broad-leaved dock are edible at several stages. The most tender leaves and best lemony flavor comes from young leaves, before the flower stalk develops. Pick the two to six youngest leaves at the center of each clump. They may not even have fully unfurled and they will be very mucilaginous.
From early to mid spring, young leaves are tasty raw or cooked. If using raw leaves, you can avoid excessive mucilage by removing the leaf stem (petiole) and using only the actual leaves in salads.
In mid to late spring, the flower stem begins to grow, and leaves from the stem may be tasty if you've had plentiful rain and cool temperatures. Dry growing conditions and high temperatures generally result in more fibrous plant tissue and astringent flavor. Sample a leaf before picking.
Flavorful, tender stem leaves can be eaten raw. If the foliage seems a little tough but still has good flavor, it should be boiled or sautéed.
Dock leaves are unusual in that when they are bruised, they may show red discoloration. These leaves, if otherwise young and fresh, are fine to eat. On mature leaves, a reddish midrib may indicate the foliage is too mature to be tasty.
The midribs of large dock leaves can be tough and fibrous, while the leaf blade remains tender. If you find a plant with tasty foliage but tough midribs, remove the midrib from the leaf before cooking. Additionally, larger petioles may be tough but pleasantly sour. Consider chopping the petioles into small pieces, and cooking them as a substitute for rhubarb or Japanese knotweed.
By early summer, most docks will have flowered, at which point they are no longer tasty wild greens. However, if you find a dock plant growing in cool shade that has not flowered even if it's mid-July, try a leaf. It won't hurt you, and if it's still tender and tasty you'll be glad you did.
In the Kitchen
Like so many greens, docks reduce in volume when cooked, to about 20-25% of their original volume. The application of heat also changes dock's texture from slightly papery to creamy, and the color from bright green to a dull, brownish-green. Slight astringency in raw leaves may be transformed to mild lemony deliciousness by cooking, so if your raw harvest tastes only slightly astringent, consider using it as a cooked green. If tasting the raw leaf causes you to make the Face of Disgust, it's not worth bringing home to the kitchen.
Boil or sauté your dock greens to make the most of their flavor. They are excellent in stir-fries, soups, stews, and egg dishes. I especially love dock with cream and cheese, and not just because cream and cheese are delicious. There's something about the texture and flavor of cooked dock that works wonderfully with dairy. Dock custard surprises me with its outstanding flavor every time I taste it.
Because dock has a relatively short harvest season, like so many wild greens, harvest as much as you can when it's at its peak, then blanch and freeze for later use. Dock is considered an invasive weed in fifteen states, so you probably won't make a dent in the local population. And next February, when the promise of spring greens seems like a cruel culinary tease, you can pull a vacuum sealed bag of dock from your well-stocked chest freezer and bask in the glory that is Rumex.