Curly Dock is a coarse plant, considered a weed; it is a naturalized, erect perennial that grows 4 to 5 feet high on a ribbed hairless stem that is usually unbranched below the inflorescence.
Leaves: Curly Dock has alternate, pointed lance shape leaves that have a distinctive curly but smooth edge. The tips are pointed, the base on the lower leaves will be slightly heart-shaped, the upper leaves have a tapered base. The upper surface is a dull green, hairless and all leaves have a stalk.
The inflorescence is a stalked panicle of racemes that form a whorl around the upper part of the stem, not spreading outward but ascending along the main stem. The whorl may be interrupted at the base. These racemes elongate during the flowering season, presenting a continuous flowering period.
The flowers are small, 6-parted with petals and sepals combined into tepals. Three of these are outer and small while the 3 inner are larger with one being distinctly larger than the others, with the central vein of one enlarging into a tubercle; on the other two large sepals a seed forms. The tubercle helps in flotation when the seed capsules dry and disperse. There are 6 stamens with yellow anthers, and 3 styles. Some flowers on the plant will be male only, while others will be bisexual and are pollinated by the wind. Each flower has a drooping stalk.
Seed: Fruit is a dry reddish-brown seed usually with the dried parts of the perianth attached. Seeds a bit pear shape with a slight curve and a narrow point at one end. Some species use a hollow tubercle as a means of flotation when the seed lands on water. When the fruit first detaches from the stem of Curly Dock, the dried perianth and the tubercle are still attached.
Habitat: Curly Dock is a plant of roadsides, pastures and field edges and easily infiltrates open areas and become invasive. It grows from a taproot and spread by re-seeding.
Names: The genus name, Rumex, is the Latin name for Docks and probably derived from 'rumo', meaning 'to suck' which alludes to an old Roman practice of sucking the leaves of docks to obtain moisture. The species name, crispus, means 'closely curled' referring to the nature of the leaf. The plant was originally classified in the genus Lapathum, which name was derived from Greek and meant "to cleanse" which was a way of referring the the plants medicinal value as a purgative. The genus Rumex is quite extensive world-wide and R. crispus is the most found member, occurring throughout the world except, perhaps, Antarctica. The alternate common name of Yellow Dock refers to the color of the inside of the root. See notes below. The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Above: The green flowers of early July with crinkly (curly) leaf edges. Leaves have a wide stalk and a thick midvein.
Below: The 3 larger tepals make a 3-sided enclosure when viewed from the bottom (1st photo). On the larger tepal main vein forms a tubercle which turns reddish (2nd photo) as the flower matures before finally turning dark brown at maturity (3rd photo). Seeds illustrated below.
Below: Detail of the green flowers. The triangular shaped form is made by the 3 larger tepals and on the central vein of the largest tepal has developed a tubercle.
Below: Seed: 1st photo - Seeds still attached to the dry perianth parts. Usually 2, a bit curved with a sharp point. The tubercle is larger and on the 3rd side.
Below: An illustration of how Curly Dock will infiltrate an area. This spot at the North end of the Upland Garden was cleared of undergrowth and invasive shrubs beginning in 2004 and then replanted with native wild flowers. Note how the dock has made an opportunity of the open space.
Notes: Curly Dock was listed on Martha Crone's 1951 inventory of plants in the Garden at that time. Found throughout Minnesota, but not in all counties, and found throughout North America. A European import. In Europe Docks have a long medicinal history.
Toxicity: The plant contains large amounts of Oxalic Acid and tannic acids. If ingested, these can cause severe digestive track, urinary track and kidney irritations.
Edibility: The young leaves of the plant are very high in vitamins and iron and are edible but due to the toxic elements they must be cooked with two or more changes of water, which is standard procedure to eliminate the toxic effects of plants that are otherwise not edible.
Lore and Uses: There is little recorded as to practical uses for the plant but there are extensive writings on the medicinal uses and it was a listed plant in the U.S. in National Formulary 4. It's use was as an alterative, astringent, laxative, anti-scorbutic and as a tonic. All the docks have compounds that can be used medicinally but Curly (or Yellow) Dock is the most important and it is the root that is used. The root is carrot shaped, yellow to orange inside, 8 to 12 inches long and about 1/2 inch thick. Plants that grow in or near water do not produce usable roots. For plants growing in dryer soils, the deeper the inside color of the root, the more potent the plant is. Roots were usually collected in fall, the later the better. In Europe, March was collection time - but before new season growth. The plant was used by Native Americans, old time doctors, settlers and herbalists. Densmore (Ref.#5) lists the plant as used by the Chippewa of Minnesota.
The active chemical constituents are Rumicin, Chrysarobin (an acid), emodin and tannin. While some dry forms were used, solutions prepared with alcohol were the most common. Even a syrup was made to be taken in teaspoonful does. Aliments that were treated were conditions of the blood and glandular system, skin diseases, liver stimulant and tumors - such that preparations of R. crispus were considered a useful cancer treatment, prior to the use of modern drugs and other therapies.
You will find considerable information in Hutchens (Ref.#12), Moore (Ref.#30), Tilford (Ref.#39) and Grieve (Ref.#7).
As Moore states in his book "The big weed is hardly graceful of demeanor and most sensible gardeners would avoid introducing it intentionally".
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"