Tumble Pigweed-Pigweed Family
Characteristics. These annuals occur mainly in cultivated, disturbed or waste sites. Tumble pigweed once mature breaks off at soil levels and tumbles with the wind (much like tumble weed) spreading its seeds over a large area. Tumble pigweed is native to North America, the center of origin is believed to be the prairie states of the central U.S. It can be found throughout the continental U.S., Canada, and in Europe. It may be found in New Zealand and South Africa, although finding it is rather uncommon (3). Prostrate Pigweed is native to the western United States. Habitats of both include fields, cropland, gardens, vacant lots, construction sites, landfills, areas along railroads and roads, and waste areas.
Identifying Characteristics. Prostate pigweed is a summer annual with branched stems up to 2' long; it is more or less prostrate. The rather succulent stems are rather terete, smooth, and glaucous; they vary in color from whitish green to pale red. The alternate leaves are up to 2" long and half as much across; they are dark green, glabrous, obovate (spoon-shaped), and smooth along the margins. Each leaf tapers gradually to a slender petiole. This is a typical field weed. Prostrate Pigweed is easy to identify because of its prostrate habit and spoon-shaped leaves. Other Amaranth spp. (Pigweeds, Amaranths) in Illinois are more erect and their leaves are more lanceolate in shape. An exception is Amaranthus tuberculatus var. prostratus (Prostrate Water Hemp). This rare plant has a prostrate habit, but its leaves are lanceolate, rather than spoon-shaped, and its female flowers have fewer sepals. Prostrate Pigweed superficially resembles Portulaca oleracea (Common Purslane). However, this latter species produces small flowers with yellow petals and its leaves lack the conspicuous lateral veins that can be found on the leaves of Prostrate Pigweed. Some authorities use the scientific synonym Amaranthus graecizans for Prostrate Pigweed.
With prostrate pigweed short clusters of
light green flowers develop from the axils of the leaves. Each plant is
monoecious and produces separate male (staminate) and female flowers
(pistillate). The male flowers have 4-5 sepals, 3 stamens, and no petals, while
the female flowers have 4-5 sepals, an ovary with 3 styles, and no petals. The
sepals of both kinds of flowers are about 1/8" in length or a little
longer and oblong-lanceolate in shape. Underneath the flowers, are several
bracts that are the same length or a little larger than the sepals. Like the
sepals, the bracts are light green and oblong-lanceolate; their tips are
pointed, but not spiny. The blooming period occurs from early summer into the
fall; individual plants can bloom for about 1-3 months. The flowers are
wind-pollinated. Each flower is replaced by a bladder-like capsule (or utricle)
containing a single seed; this capsule is globoid and smooth while young.
Later, it splits open around the middle to release the seed. The seeds are
1.1–1.7 mm. across; they are dark brown or black, shiny, round in
circumference, and somewhat flattened. The root system consists of a stout
taproot. This plant spreads by reseeding itself.
Tumble pigweed stems are glabrous and pale green to whitish in color. The immature plant has small egg-shaped leaves (less than 1.5 inches in length) with wavy edges. The mature plant is somewhat bushy in appearance, being multi branched with an ascending tip and rarely more than one meter tall. Leaf size and shape is similar to the immature plant and the coloration is typically pale green on the upper surface and pale green to reddish-tinged on the underside (1). Male and female organs are produced in different flowers on the same plant (monoecious). From July through August, greenish flowers are produced in short, dense clusters in the leaf axils.
Tumble (left), Prostrate Pigweed (middle) and Leaves of Prostrate (Right).
Prostrate pigweed (A. blitoides) and tumble pigweed are similar in appearance as seedlings. However, as mature plants, tumble pigweed is multi-branched bushy and grows upright while prostrate pigweed displays a prostrate, ground hugging appearance. When mature tumble pigweed is compared to mature smooth pigweed (A. hybridus) and redroot pigweed (A. retroflexus), the inflorescence is the distinguishing characteristic. All three plants grow upright, but the flowers of tumble pigweed grow in dense, short, axillary clusters while the other two species produce flowers on terminally branched spikes.
Male and female organs are produced in different flowers on the same plant (monoecious). The pollination biology of tumble pigweed is not definite; other monoecious species of Amaranthus are self-compatible, and generally wind-pollinated (3). July through August, greenish flowers are produced in short, dense clusters in the leaf axils.
Both pigweeds are abundant producers of seed and are reproduced only by seed. A recent study by the University of Missouri reported seed production of approximately 50,000 seeds per plant . Fruit produced are thin-walled; one seeded inflated structures (utricles) 1.3 to 1.7 mm long, opening around the middle by a cap like lid. Seeds are small (0.7 to 1.5 mm in diameter) shiny black, round and convex on both sides . Seed dispersal is usually accomplished by the breaking of older plants at the soil surface. The breaking allows the plant to tumble in the wind dispersing seeds. Russian thistle (Salsola iberica) is like tumble pigweed in that they both disperse seed by tumbling. Russian thistle has smaller leaves and distinct spiny foliage.
Mechanical methods of control can also be implemented and should prove to be effective especially if there is a cool, wet spring. This type of weather will slow the initial growth process and allow for cultivation equipment to disrupt the immature plants growing cycle.
Not all amaranth plants are cultivated. Most of the species from Amaranthus are summer annual weeds and are commonly referred to as pigweeds. These species have an extended period of germination, rapid growth, and high rates of seed production and have been causing problems for farmers since the mid-1990s. This is partially due to the reduction in tillage, reduction in herbicidal use and the evolution of herbicidal resistance in several species where herbicides have been applied more often. The following 9 species of Amaranthus are considered invasive and noxious weeds in the U.S and Canada: A. albus, A. blitoides, A. hybridus, A. palmeri, A. powellii, A. retroflexus, A. spinosus, A. tuberculatus, and A. viridis.
A new herbicide-resistant strain of Amaranthus palmeri or Palmer amaranth has appeared; it is Glyphosate-resistant and so cannot be killed by the widely used Roundup herbicide. Also, this plant can survive in tough conditions. This could be of particular concern to cotton farmers using Roundup Ready cotton. The species Amaranthus palmeri (Palmer amaranth) causes the greatest reduction in soybean yields and has the potential to reduce yields by 17-68% in field experiments. Palmer amaranth is among the “top five most troublesome weeds” in the southeast and has already evolved resistances to dinitroanilines and acetolactate synthase inhibitors. This makes the proper identification of Amaranthus species at the seedling stage essential for agriculturalists. Proper herbicide treatment needs to be applied before the species successfully colonizes in the crop field and causes significant yield reductions.
Pigweed can be a beneficial weed, as well as a companion plant, serving as a trap for leaf miners and some other pests, as well as sheltering ground beetles (which prey upon insect pests) and breaking up hard soil for more delicate neighboring plants
Amaranthus Genus-Uses. Amaranthus, collectively known as amaranth, is a cosmopolitan genus of herbs. Approximately 60 species are recognized, with inflorescences and foliage ranging from purple and red to gold. Members of this genus share many characteristics and uses with members of the closely related genus Celosia.
Although several species are often considered weeds, people around the world value amaranths as leaf vegetables, cereals, and ornamentals. A traditional food plant in Africa, amaranth has the potential to improve nutrition, boost food security, foster rural development and support sustainable landcare.
Amaranthus shows a wide variety of morphological diversity among and even within certain species. Although the family (Amaranthaceae) is distinctive, the genus has few distinguishing characters among the 70 species included. This complicates taxonomy and Amaranthus has generally been considered among systematists as a “difficult” genus.
Currently, Amaranthus includes 3 recognized sub-genera and 70 species, although species numbers are questionable due to hybridization and species concepts. Infrageneric classification focuses on inflorescence, flower characters and whether a species is monoecious/dioecious. Several species are raised for amaranth "grain" in Asia and the Americas. This should more correctly be termed "pseudograin". They are highly edible by gluten intolerant individuals because they are not a member of the grass family and contain no gluten.
Ancient amaranth grains still used to this day include the three species, Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus. Although amaranth was (and still is) cultivated on a small scale in parts of Mexico, Guatemala, Peru, India, and Nepal, there is potential for further cultivation in the U.S and tropical countries and it is often referred to as "the crop of the future." It has been proposed as an inexpensive native crop that could be cultivated by indigenous people in rural areas for several reasons: 1) it is easily harvested, 2) it produces lots of fruit and thus seeds, which are used as grain, 3) it is highly tolerant of arid environments, which are typical of most subtropical and some tropical regions, and 4) its seeds contain large amounts of protein and essential amino acids, such as lysine. 5) Amaranthus species are reported to have a 30% higher protein value than cereals, such as rice, wheat flour, oats, and rye. 6) It requires little fuel to cook. As befits its weedy life history, amaranth grains grow very rapidly and their large seed heads can weigh up to 1 kilogram and contain a half-million seeds. Amaranth grain is a crop of moderate importance in the Himalaya.
Because of its importance as a symbol of indigenous culture, and because it is very palatable, easy to cook, and its protein particularly well suited to human nutritional needs, interest in grain amaranth (especially A. cruentus and A. hypochondriacus) revived in the 1970s. It was recovered in Mexico from wild varieties and is now commercially cultivated. It is a popular snack sold in Mexico City and other parts of Mexico, sometimes mixed with chocolate or puffed rice, and its use has spread to Europe and parts of North America. Amaranth and quinoa are called pseudograins because of their flavor and cooking similarities to grains. These are dicot plant seeds, and both contain exceptionally complete protein for plant sources. Besides protein, amaranth grain provides a good source of dietary fiber and dietary minerals such as iron, magnesium, phosphorus, copper, and especially manganese. It has been claimed to be beneficial in preventing greying of hair.
Amaranth species are cultivated and consumed as a leaf vegetable in many parts of the world. There are 4 species of Amaranthus documented as cultivated vegetables in eastern Asia: Amaranthus cruentus, Amaranthus blitum, Amaranthus dubius, and Amaranthus tricolor.
Root of mature amaranth is an excellent vegetable. It is white in color and is cooked with tomatoes or tamarind gravy. It has a milky taste and is alkaline.
In China, the leaves and stems are used as a stir-fry vegetable, or in soups and variations on this transliteration in various dialects). Amaranth greens are believed to help enhance eyesight. In Vietnam, it is called rau dền and is used to make soup. There are two species popular as edible vegetable in Vietnam: dền đỏ- amaranthus tricolor and dền cơmor dền trắng- amaranthus viridis.
In Greece, Green Amaranth (Amaranthus viridis) is a popular dish and is called vlita or vleeta. It's boiled, then served with olive oil and lemon like a salad, usually alongside fried fish. Greeks stop harvesting the (usually wild-grown) plant when it starts to bloom at the end of August. In Sri Lanka, it is called "Koora Thampala". Sri Lankans cook it and eat it with rice. Fiji Indians call it choraiya bhaji.
Dyes. The flowers of the 'Hopi Red Dye' amaranth were used by the Hopi (a tribe in the western United States) as the source of a deep red dye. There is also a synthetic dye that has been named "amaranth" for its similarity in color to the natural amaranth pigments known as betalains. This synthetic dye is also known as Red No. 2 in North America and E123 in the European Union.
Ornamentals. The genus also contains several well-known ornamental plants, such as Amaranthus caudatus (love-lies-bleeding), a native of India and a vigorous, hardy annual with dark purplish flowers crowded in handsome drooping spikes. Another Indian annual, A. hypochondriacus (prince's feather), has deeply veined lance-shaped leaves, purple on the under face, and deep crimson flowers densely packed on erect spikes.
Amaranth greens, also called Chinese spinach, hinn choy or yin tsoi (simplified Chinese: 苋菜; traditional Chinese: 莧菜; pinyin: xiàncài); callaloo, dhantinasoppu (Kannada); తోటకూర (Telugu);Rajgira (Marathi); முளைக் கீரை (Tamil), cheera ചീര (Malayalam); bayam (Indonesian); phak khom ผักโขม (Thai); tampala, or quelite, (Oriya); Khada Saga, are a common leaf vegetable throughout the tropics and in many warm temperate regions. It is very popular in India. They are a very good source of vitamins including vitamin A, vitamin K, vitamin B6, vitamin C, riboflavin, and folate, and dietary minerals including calcium, iron, magnesium, phosphorus, potassium, zinc, copper, and manganese. Because of its valuable nutrition, some farmers grow amaranth today.
Amaranth seeds, like buckwheat and quinoa, contain protein that is unusually complete for plant sources. Most fruits and vegetables do not contain a complete set of amino acids, and thus different sources of protein must be used.
Its seeds have a protein content greater than that of wheat. However, unlike that found in true grains (i.e. from grass seeds) its protein is not of the problematical type known as gluten.
Several studies have shown that like oats, amaranth seed or oil may be of benefit for those with hypertension and cardiovascular disease; regular consumption reduces blood pressure and cholesterollevels, while improving antioxidant status and some immune parameters. While the active ingredient in oats appears to be water-soluble fiber, amaranth appears to lower cholesterol via its content of plant stanols and squalene.