Pigweed

August 09, 2022

Melissa and I were watching a show on PBS last week concerning climate change and the fragile nature of the earth.  One of the persons interviewed was Neil deGrasse Tyson, an American astrophysicist, author, and science communicator.  Tyson’s comments addressed the effect of raising or lowering temperatures.  During the last ice age, the earth’s average temperature was only 8F (14.5C) less than today.  By contrast, the proposed 2F (3.5C) rise predicted by 2050 (if we control the greenhouse gasses) would result in widespread draught.  One of the trending stories on today’s weather app was about a super plant that might allow humans to modify crops to withstand draught and high temperatures.  The invasive pigweed thrives in hot and dry areas as easily as it does in your garden.

When I looked online, I found pigweed (Amaranthus retroflexus) is a species of flowering plant in the family Amaranthaceae with several common names, including red-root amaranth, redroot pigweed, and common tumbleweed.  Pigweed is native to the tropical Americas and has spread as an introduced species on most continents and in a variety of habitats.  The weed is an erect, annual herb reaching a maximum height of 10 feet (3 m).  The leaves are nearly 6 inches (15 cm) long on larger plants, with those higher on the stem being lance shaped and those lower on the plant being diamond or oval.  The plant is monoecious, with individuals bearing both male and female flowers.  The inflorescence is a large, dense cluster of flowers interspersed with spiny green bracts.  The fruit is a capsule less than 0.08 inches (2 mm) long with a “lid” which opens to reveal a tiny black seed.  The common name of “pigweed” was given as it grows where hogs are pasture-fed.  You are likely to see it in your lawn or garden as it grows in a variety of conditions and resists many herbicides.  I have not seen this plant in our yard or my containers.

While researchers are looking for ways to use pigweed to genetically modify cereal grains, the plant is already eaten as a vegetable in different parts of the world.  Pigweed can be used like you would any edible green.  No species of the genus Amaranthus is poisonous, but the leaves do contain oxalic acid and may contain nitrates if grown in nitrate-rich soils, so the water should be discarded after boiling.  The young shoots and leaves can be eaten raw, and the leaves are high in calcium, iron, protein, and phosphorus.  Many Indigenous peoples in the US West used pigweed for a multitude of food and medicinal purposes and it is sold as a vegetable in some Mexican markets.  The seeds are edible raw, roasted, cooked as a hot cereal, used as a thickener, ground into flour for use as bread, and even popped like popcorn.  If you are using pigweed from your garden, be sure you have not sprayed it with pesticides or herbicides prior to harvesting.  

THOUGHTS:  Using pigweed in the kitchen is one way to manage a plant that many gardeners call a pest or weed.  There are indications that using pigweed as a fodder for cattle can have adverse effects (bloating) in large amounts and may even be toxic.  I found it interesting that there were as many sites dedicated to eradicating pigweed as there were touting the nutritional value of the plant.  Once again, the definition of a weed is something that grows where you did not plant it.  We tend to treat people in the same manner and find ways to discourage them from being in a location where they are not expected.  If we instead allow them to thrive, we will find diversity also has benefits.  Act for all.  Change is coming and it starts with you.