Pigweed can mean any of a number of weedy plants which may be used as pig fodder:
Amaranthus is a cosmopolitan genus of annual or short-lived perennial plants collectively known as amaranths. Some amaranth species are cultivated as leaf vegetables, pseudocereals, and ornamental plants. Most of the Amaranthus species are summer annual weeds and are commonly referred to as pigweeds. Catkin-like cymes of densely packed flowers grow in summer or autumn. Amaranth varies in flower, leaf, and stem color with a range of striking pigments from the spectrum of maroon to crimson and can grow longitudinally from 1 to 2.5 metres tall with a cylindrical, succulent, fibrous stem that is hollow with grooves and bracteoles when mature. There are approximately 75 species in the genus, 10 of which are dioecious and native to North America with the remaining 65 monoecious species endemic to every continent from tropical lowlands to the Himalayas. Members of this genus share many characteristics and uses with members of the closely related genus Celosia. Amaranth grain is collected from the genus. The leaves of some species are also eaten.
Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus Amaranthus. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it the most species-rich lineage within its parent order, Caryophyllales.
Amaranthus blitum, commonly called purple amaranth or Guernsey pigweed, is an annual plant species in the economically important plant family Amaranthaceae.
Amaranthus hybridus, commonly called green amaranth, slim amaranth, smooth amaranth, smooth pigweed, or red amaranth, is a species of annual flowering plant. It is a weedy species found now over much of North America and introduced into Europe and Eurasia.
Amaranthus spinosus, commonly known as the spiny amaranth, spiny pigweed, prickly amaranth or thorny amaranth, is a plant is native to the tropical Americas, but is present on most continents as an introduced species and sometimes a noxious weed. It can be a serious weed of rice cultivation in Asia.
Amaranthus retroflexus is a species of flowering plant in the family Amaranthaceae with several common names, including red-root amaranth, redroot pigweed, red-rooted pigweed, common amaranth, pigweed amaranth, and common tumbleweed.
Amaranthus palmeri is a species of edible flowering plant in the amaranth genus. It has several common names, including carelessweed, dioecious amaranth, Palmer's amaranth, Palmer amaranth, and Palmer's pigweed.
Amaranthus albus is an annual species of flowering plant. It is native to the tropical Americas but a widespread introduced species in other places, including Europe, Africa, and Australia.
Amaranthus fimbriatus is a species of glabrous flowering plant in the Amaranthaceae family. It is commonly known as fringed amaranth or fringed pigweed. The plant is an annual herb that can often grow up to 0.7 m (2 ft.) in height. The flower is greenish to maroon. It is found in North America and in Mexico. It often grows on sandy, gravelly slopes, semideserts or in disturbed habitats. It usually blooms after the summer rains in these arid regions. It is considered to be an invasive weed.
Prostrate pigweed is a common name for several plants and may refer to:
Species belonging to the genus Amaranthus have been cultivated for their grains for 8,000 years. Amaranth plants are classified as pseudocereals that are grown for their edible starchy seeds, but they are not in the same botanical family as true cereals, such as wheat and rice. Amaranth species that are still used as a grain are Amaranthus caudatus L., Amaranthus cruentus L., and Amaranthus hypochondriacus L. The yield of grain amaranth is comparable to rice or maize.
Amaranthus blitoides, commonly called mat amaranth, prostrate pigweed, procumbent pigweed, prostrate amaranth, or matweed, is a glabrous annual plants species. It usually grows up to 0.6 m, though it may grow up to 1 m. It flowers in the summer to fall.
Amaranthus cannabinus is a plant species also known as salt marsh water hemp or salt marsh pigweed. It is a herbaceous perennial found in most of the eastern United States. It grows from 1 to 3 m in height. It is often mistaken for Amaranthus australis.
Amaranthus deflexus is also known by the common names low amaranth, Argentina amaranth, perennial pigweed, and large-fruit amaranth. It is native to South America, and has been introduced to many other parts of the world. It is a short-lived perennial or annual plant. The plant can grow up to 1.5 ft in height.
Purple amaranth is a common name for several plants in the genus Amaranthus and may refer to:
Amaranthus graecizans, the Mediterranean amaranth or short-tepalled pigweed, is an annual species in the botanical family Amaranthaceae. It is native to Africa, southern Europe, East Asia to India and Central Asia. It is naturalized in North America. More general common names include tumbleweed and pigweed.
Spiraea thunbergii (珍珠绣线菊), Thunberg spiraea or Thunberg's meadowsweet, is a species of flowering plant in the rose family, native to East China and Japan, and widely cultivated elsewhere.
Water-hemp or waterhemp is a common name for several plants and may refer:
Lamb's quarter, lambsquarters, and similar terms refer to any of various edible species of herbaceous plants otherwise known by the common names goosefoot or pigweed.
Hogweed is a common name for several unrelated plants.