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, 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 with a stalk; the upper leaves have a tapered base and usually stalkless. The upper surface is a dull green, hairless and all leaves have a stalk. Leaves join the stem with a sheath and ocrea - the ocrea usually not persisting on the mature plants.
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 grouped 10 to 25 in fascicles and whorl around the panicle racemes.
The flowers are a bit unusual - small, 6-parted with petals and sepals combined into tepals. Three of these are outer and remain small while the 3 inner enlarge but are only 3.5-6 by 3-5 mm in size - deltate shape. Each flower has 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 from the fascicle node. A turbercle (warty growth) usually forms on the central vein of all three of the inner tepals and one usually has a distinctly larger tubercle. These become the seeds.
Seed: Fruit is a dry reddish-brown achene sharply 3-angled, 2 to 3 mm long and 1.5 to 2 mm wide. Seeds are a bit pear shaped with a slight curve and a narrow point at one end. Some species of plants 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 which provides a wing for air transport.
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 author name for the plant classification from 1753 - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
The plant was at one time re-classified as Lapathum crispum, by Giovanni Antonio Scopoli (1723-1788) but that is not accepted. That name was derived from Greek and meant "to cleanse" which was a way of referring to 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 medicinal notes below.
Above: The green flowers of early July with leaves showing their crinkly (curly) leaf edges.
Below: 1st photo - Leaves have a wide stalk and a thick midvein. 2nd photo - the ocrea of the leaf/stem node.
Below: The 3 larger tepals make a 3-sided enclosure when viewed from the bottom (1st photo). On the larger tepals main veins, there usually forms a tubercle - one usually larger than those on the other 2 large tepals. These turn 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 visible tepal has developed a tubercle.
Below: Seed: 1st photo - Tubercles still attached to the dry perianth tepal parts. Usually there are 3 but can vary from 1 to 3; they are a bit curved with a sharp point with one of the three larger than the others.
Below: The long taproot of Curly Dock.
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 in 2004 to 2008, then replanted with native wild flowers in 2008 and one year later you see this new growth and note how the dock has made an opportunity of the new 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.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"