Pokeweed-also known by a number of other names-is native to eastern North America, the Midwest, and the Gulf Coast, with more scattered populations in the far West.[not verified in body] It is considered a major pest species by farmers,[not verified in body] and that and the danger of human poisoning-its significant toxicity and its risks to human and animal health are consistently reported, with the whole of the plant toxic and increasing in toxicity through the year, with children at particular risk of its very poisonous purple-red ripe fruit-support arguments for eradication of P. americana. Even so, it is used as an ornamental in horticulture, and it provokes interest for the variety of its natural products (toxins and other classes), for its ecological role, its historical role in traditional medicine, and for some utility in biomedical research (e.g., in studies of pokeweed mitogen). In the wild, it is easily found growing in pastures, recently cleared areas, and woodland openings, edge habitats such as along fencerows, and in waste places.It has simple leaves on green to red or purplish stems and a large white taproot. The flowers are green to white, followed by purple to almost black berries which are a food source for songbirds such as gray catbird, northern mockingbird, northern cardinal, and brown thrasher, as well as other birds and some small animals (i.e., to species that are unaffected by its mammalian toxins).American pokeweed (Phytolacca americana), or simply pokeweed, is a herbaceous perennial plant in the pokeweed family Phytolaccaceae growing up to 8 feet (2 meters) in height. It is native to the eastern United States and has significant toxicity.
Pokeweed is a member of the Phytolaccaceae, or broader pokeweed family, and is a native herbaceous perennial plant, that is large, growing up to 8 feet (2 meters) in height. One to several branches grow from the crown of a thick, white, fleshy taproot, each a "stout, smooth, green to somewhat purplish stem;" with simple, entire leaves with long petioles alternately arranged along the stem.
Pokeweeds reproduce only by its seeds (large glossy black, and lens-shaped), contained in a fleshy, 10-celled, purple-to-near-black berry with crimson juice. The flowers are perfect, radially symmetric, white or green, with 4-5 sepals and no petals. The flowers develop in elongated clusters termed racemes. The seeds have a long viability and can germinate after many years in the soil.
Birds are unaffected by the natural chemicals contained in the berries (see below), and eat them, dispersing the seeds. Seed are also found in commercial seed (e.g., vegetable seed packets). The berries are reported to be a good food source for songbirds and other bird species and small animals unaffected by its toxins. Distribution via birds is thought to accounts for the appearance of "single, isolated plants" in areas that had otherwise not been populated by pokeweed.
P. americana is known as pokeberry,poke root, or inkberry, also as Virginia poke or simply poke, as pigeonberry, or redweed or red ink plant, or, in Chinese medicine, chuíxù shānglù (-序-). The plant is also referred to as poke sallet or polk salad, and this and related terms can also refer to the cooked leaves of the plant, see Cultural significance below.
The information with regard to the overall and significant toxicity of this plant and the risks to human and mammalian health it poses is consistent and pervasive. In summary, with regard to distribution through the plant: the poisonous principles are found in highest concentrations in the rootstock, then in leaves, and stems, and then in the ripe fruit, the plant generally gets more toxic with maturity, with the exception of the berries (which have significant toxicity even while green).
With regard to human and animal (pet and livestock) toxicity, the Ohio Agricultural Research and Development Center (OARDC) staff scientists note that "[a]ll parts of common pokeweed are toxic... Roots are the most poisonous, leaves and stems are intermediate in toxicity (toxicity increases with maturity), and berries are the least toxic." With regard to human poisoning they note:
As summarized by Michael D.K. Owen, for the Iowa State University Extension Service:
A further well-referenced web reference on the toxicity states that pokeweed is to be avoided during pregnancy and notes that "children consum[ing] even one berry" require emergency treatment; in terms of general exposure, it notes "plant sap can cause dermatitis in sensitive people" and that "it is strongly recommended that the people wear gloves when handling the plant."
Regarding pet, livestock, and other mammalian poisoning, Owen notes that "birds are apparently immune to this poison" and that "animals usually do not eat the plant because of its bitter taste." The OARDC scientists echo the lack of animal palatability, and note that "most animals avoid eating it unless little else is available, or if it is in contaminated hay. Horses, sheep and cattle have been poisoned by eating fresh leaves or green fodder, and pigs have been poisoned by eating the roots."
Human deaths resulting from pokeweed consumption are uncommon, but cases of emesis and catharsis are known, and a child who consumed crushed seeds in a juice is reported to have died. Historically, pokeweed poisonings were common in eastern North America during the 19th century, especially from the use of tinctures as antirheumatic preparations and from ingestion of berries and roots that were mistaken for parsnip, Jerusalem artichoke, or horseradish.
See the #Natural products section for specific information about the known toxicities of the constituents of the plant.
The OARDC staff scientists note that immediate and subsequent symptoms of poisoning from pokeweed include "a burning sensation in the mouth, salivation, gastrointestinal cramps, and vomiting and bloody diarrhea," and that depending upon the amount consumed, more severe symptoms can occur, including "anemia, altered heart rate and respiration, convulsions and death from respiratory failure." If only small quantities of the plant or its extracts are ingested, people and animals may recover within 1 to 2 days.
Pokeweed also has appeared in Southern Ontario, Canada. Large 8 foot plant appeared 5 years ago and continues to appear regularly every year. If clumps of ripe berries are dispersed about and left over winter, new shoots arrive in the spring and continue to appear every year. Blooms until frost in zone 6. It is unknown if there are any other plants appearing in the Niagara Peninsula.
Owen reports that pokeweed "[u]sually... grows in rich pasture lands, in recently cleared areas, along fencerows, and in waste places and open spots in woodlands." It is broadly distributed in these places and in fields and in edge habitats.
It is adapted to coarse or fine soils with moderate moisture, high calcium tolerance but low salinity tolerance, pH tolerance from 4.7-8. The plant grows well in sun or shade, and readily survives fire due to its ability to resprout from the roots. Pokeweed seeds do not require stratification and are dispersed by berry-feeding birds.
Pokeweed is found in most of the continental United States, except the northern plains and mountain states.[original researc][this quote needs a citation] In recent years the plant appears to have increased in populated places.[not in citation given][not in citation given]
Plant Type: Perennial herbaceous plant which can reach a height of 10 feet (3 meters), but is usually 4 ft (1.2 m) to 6 ft (2 m). However, the plant must be a few years old before the root grows large enough to support this size. The stem is often red as the plant matures. There is an upright, erect central stem early in the season, which changes to a spreading, horizontal form later in the season with the weight of the berries. Plant dies back to roots each winter. Stem has a chambered pith.
Leaves: The leaves are alternate with coarse texture with moderate porosity. Leaves can reach sixteen inches in length. Each leaf is entire. Leaves are medium green and smooth with what some characterize as an unpleasant odor.
Flowers: The flowers have 5 regular parts with upright stamens and are up to 0.2 inches (5 mm) wide. They have white petal-like sepals without true petals, on white pedicles and peduncles in an upright or drooping raceme, which darken as the plant fruits. Blooms first appear in early summer and continue into early fall.
Fruit: A shiny dark purple berry held in racemous clusters on pink pedicels with a pink peduncle. Pedicles without berries have a distinctive rounded five part calyx. Fruits are round with a flat indented top and bottom. Immature berries are green, turning white and then blackish purple.
Root: Thick central taproot which grows deep and spreads horizontally. Rapid growth. Tan cortex, white pulp, moderate number of rootlets. Transversely cut root slices show concentric rings. No nitrogen fixation ability.[not in citation given][not in citation given][better source needed]
Various sources discuss notable chemical constituents of the plant.[full citation needed][better source needed] Owen of Iowa State University notes that the "entire pokeweed plant contains a poisonous substance similar to saponin" and that the "alkaloid phytolaccine also occurs in small amounts." Heller at the National Library of Medicine notes the two natural products, the alkaloid phytolaccatoxin and phytolaccagenin, as contributing to human poisoning. The Canadian Poisonous Plants Information System echoes the information about phytolaccine and phytolaccatoxin.
Other toxic components include triterpene saponins based on the triterpene genins, phytolaccagenin as noted, and jaligonic acid, phytolaccagenic acid (phytolaccinic acid), esculentic acid, and pokeberrygenin, and phytolaccasides A, B, D, E, and G, and phytolaccasaponins B, E, and G.[non-primary source needed]
Triterpene saponins isolated from the berries of pokeweed uncharacterized as to toxicity include esculentoside E; and phytolaccasides C and F, and oleanolic acid, and 3-oxo-30-carbomethoxy-23-norolean-12-en-28-oic acid. Triterpene alcohols isolated include α-spinasterol and its glucoside, α-spinasteryl-β-D-glucoside, and a palmityl-derivative, 6-palmytityl-α-spinasteryl-6-D-glucoside, as well as a similarly functionalized stigmasterol derivative, 6-palmityl-7-stigmasterol--D-glucoside.
Other than starch and various tannins, other small molecule natural products isolated from pokeweed include canthomicrol, astragalin, and caryophyllene. Seeds contain the phenolic aldehyde caffeic aldehyde.
Proteins of interest include various lectins, protein PAP-R, and pokeweed mitogen (PWM), as well as a toxic glycoprotein.
Pokeweed berries are reported to be a good food source for songbirds such as gray catbird (Dumetella carolinensis), northern mockingbird (Mimus polyglottos), northern cardinal (Cardinalis cardinals), and brown thrasher (Toxostoma rufum), other bird species including mourning dove (Zenaida macroura), and cedar waxwing (Bombycilla cedrorum), and small mammals apparently tolerant of its toxins, including raccoon, opossum, red and gray fox, and the white-footed mouse.
Pokeweeds are used as sometime food sources by the larvae of some Lepidoptera species, including the giant leopard moth (Hypercompe scribonia).
Some pokeweeds are grown as ornamental plants, mainly for their attractive berries; a number of cultivars have been selected for larger fruit panicles.
Owen notes that "Indians and early settlers used the root in poultices and certain drugs for skin diseases and rheumatism."
The late 19th century herbal, the King's American Dispensatory, describes various folk medical uses that led individuals to ingest pokeberry products.
Pokeweed is promoted in alternative medicine as a dietary supplement that can treat a wide range of maladies including mumps, arthritis and various skin conditions. While pokeweed has been subject to laboratory research, there is no medical evidence that it has any beneficial effect on human health.
Poke is a traditional southern Appalachian food. The leaves and stems can both be eaten, but must be cooked, usually boiled three times in fresh water each time. The leaves have a taste similar to spinach; the stems taste similar to asparagus. To prepare stems, harvest young stalks prior to chambered pith formation, carefully peel the purple skin away, then chop the stalk up and fry in meal like okra. Traditionally, poke leaves are boiled, drained, boiled again, then fatback is added and cooked some more to add flavor. Poisonings occur from failure to drain the water from the leaves at least once. Preferably they should be boiled, drained, and water replaced two or more times.
As noted by the OARDC staff scientists:
Although all parts of the plant are considered toxic and the root is never eaten and cannot be made edible, the late 19th century herbal, the King's American Dispensatory, describes various folk medical uses that led individuals to ingest pokeberry products, and festivals still celebrate the plant's use in its historical food preparations (see below). Authorities[wh] advise against eating pokeweed even after thrice boiling, as traces of toxins may still remain, and all agree pokeweed should never be eaten uncooked.
Plant toxins from Phytolacca are being explored as a means to control zebra mussels.
The toxic extract of pokeweed berries can be processed to yield a red ink or dye.[better source needed]
During the middle of the 19th century wine often was coloured with juice from pokeberries.
The cultural significance of poke sallet, the cooked greens-like dish made from pokeweed, and the rural poverty reflected in its history, is indicated by the popularity and coverage received by the 1969 hit swamp rock song "Polk Salad Annie", written and first performed by Tony Joe White. The opening lyrics run:
The song has been covered many times, most famously by Elvis Presley (appearing on several of his albums), by Big Twist and The Mellow Fellows, Tom Jones, Johnny Hallyday, Bill Carlisle, Joe Dassin, and others.[better source needed]
Poke sallet festivals are held annually in several small southern communities, in remembrance of the plant and its historic role, festivals that have evolved to be local community celebrations only remotely related to the plant as a food or medicinal (e.g., and individual festival references below). Published locations for the continuing festivals include:
Bearing toxicity information in mind (see section above), nutritional information for boiled and drained pokeberry shoots has been reported (see box).
Bearing toxicity information in mind (see section above), nutritional information per 100 grams dry weight of shoots has been reported:[better source needed]