Figure 3. a. Feeding in the pigweed flea beetle, Volenberg, D. S., W. L. Patzoldt, A. G. Hager, and P. J. Tranel. Because pigweeds produce seed so prolifically, it is critical to minimize the annual seed rain onto the soil. Photo credit: Mark Schonbeck, Virginia Association for Biological Farming. Newly shed pigweed seeds are mostly dormant, and become less so by the following spring. Note also that the National Organic Program requires a 120-day interval between manure deposits by grazing animals and the next food-crop harvest. Has a smaller one growing beside it. Pigweed identification: a Pictoral guide to the common pigweeds of the Great Plains. Pigweeds resistant to HPPD-inhibitors, ALS-inhibitors, glyphosate, and atrazine sweep across the state. However, in upstate New York, 2–4-inch fragments of Powell amaranth inflorescences lying on the soil surface were found to contain black seeds 3 weeks after the weeds were disked down at flowering (Charles Mohler, Cornell University, pers. A carpet of spiny amaranth seedlings arises from a large weed seed bank. Figure 10. Pigweed thrives in garden settings and grows wild in untended fields. One part seeds to two parts water is a happy medium. Two timely mowings prior to canopy closure have given adequate between-row control of giant foxtail, pigweeds, and ragweed in soybean planted in a 30-inch row spacing (Donald, 2000). copyright © 2010-2020 Wild Edible, all rights reserved | Privacy Policy | Terms & Conditions. Putnam, A. R., J. DeFrank, and J. P. Barnes. About 50,000–90,000 seeds weigh one ounce. Thanks for your support! Buhler, D. D. and R. G. Hartzler. Organic farmers manage pigweeds by taking advantage of their points of vulnerability. Pair of stiff, sharp ½-in spines at base of each leaf; stems smooth, hairless, often red, Slender, simple or branched terminal spikes, Throughout U.S. and southern Canada except driest areas, Male and female flowers on separate plants; stems and leaves smooth and hairless; leaves often longer and narrower than other species, Leaves small (blade about 1 in) with distinct notch at tip; seeds dull black, larger than in other pigweeds (0.06 in), Mature plants break off at ground level, and are carried by wind, dispersing seeds; stems white to pale green, leaves light green, * Small clusters of flowers are usually present in leaf axils of all amaranths, Timely cultivation, flame weeding, and manual removal, Crop rotations that vary timing of tillage and other operations, Measures to prevent or minimize production of viable seeds. When growing amaranth, harvest time depends on what you are growing the plants for. I’m gathering amaranth to collect seed to feed my chickens. Mohler, C. A. Watch the crop closely; if a significant amount of pigweed grows with it, terminate the crop promptly when weed flower heads first appear. It bears inconspicuous flowers from June to November. Also, redroot pigweed flowers are held in short, … We only link books and other products that we think would be useful to our readers. As seedlings, pigweeds other weeds by the small notch in the tip of the ... single Palmer amaranth can produce over 500,000 seeds and can grow 1 inch or more per day. Photo credits: Mark Schonbeck, Virginia Association for Biological Farming. Plant and Soil 135: 287–292. Journal of Chemical Ecology 9: 1045–1057. In organic production systems, pigweeds can be managed through a combination of: Virtually every farmer in North America knows and grapples with pigweed, a term that covers several species in the genus Amaranthus, including: These heat-loving summer annuals emerge after the spring frost date, grow rapidly, compete vigorously against warm-season crops, reproduce by seed, and die with the fall frost. University of Arkansas Division of Agriculture Cooperative Extension Service News - October 2009. Timely action is vital, as pigweeds rapidly become harder to kill once they grow taller than one inch and develop four or more true leaves (Fig. It sometimes forms dense mats and the stems can be … Alternatively, a synthetic mulch such as black plastic can be laid before crop planting, and alley weeds controlled by cultivation, mowing, organic mulch, or cover crop. Texas has 23 recorded species, which vary in growth forms from prostrate to branching upright. For heavy feeders like broccoli or spinach that need some quick N, band or side dress materials within or near the crop row at the onset of rapid crop growth. This works better if you have mesh bags. The leaves can be eaten raw or cooked like spinach, due to its mild flavour, it is adaptable to many dishes. 2). One to three pigweed plants per 10 feet of row emerging with corn or soybean can cause significant yield losses (Klingman and Oliver, 1994; Knezevic et al., 1994; Massinga et al., 2001) Pigweeds that emerge several weeks after the crop has emerged exert much less effect on yields. Figure 6. Proceedings of the Southern Weed Science Society 59: 260–277. Small amounts of pigweed can also be ued as an animal feed. In taller crops like corn, pigweeds respond to canopy shade by increasing stem growth and deploying leaves higher on the plant, thereby intercepting a larger fraction of available light (Massinga et al., 2003; McLachlan et al, 1993). 2004. Individual pigweed flowers are small, inconspicuous, and usually greenish in color. How does it taste? It's also high in vitamin A and calcium, as well as a host of other healthful vitamins and minerals. Temperature effects on germination and growth of redroot pigweed (, Horak, M. J., and T. M. Loughin. If flower heads are already formed, remove severed or uprooted pigweed plants from the field. While of the 60-70 species of amaranth, 40 are considered native to the Americas, you are likely growing one of three: A. hypochondriacus (Prince’s Feather), A. cruentus (Purple Amaranth) or A. tricolor (Tampala, which is grown chiefly for its leaves). Just last summer, under a new emergency rule, pigweed was labeled a … This should be done before pigweed flowers open (within a few days after flower heads first become visible) to prevent viable seed formation. When pigweed grows as large as the seedling on the left, it becomes more difficult to kill, requiring more vigorous cultivation. "Pigweed" is a common name for a few different plants, including lambsquarters, but the particular pigweed I'm writing about is the one whose genus is Amaranthus, also known as "amaranth.". 44. Redroot pigweed (Amaranthus retroflexus L.) is the most widespread of the three species, being found throughout the United States, in all provinces of Canada except Newfoundland, and as far north as Kenora and Cochrane in Ontario. Prostrate pigweed forms a low, spreading mat, with smaller (about one inch) leaves that are distinctly notched at the tip (Fig. Decline of weed seeds and seedling emergence over five years as affected by soil disturbances. Seeds become viable at about the same time that they develop their mature dark brown or black color. The amaranth flea beetle feeds on pigweed foliage, and has been observed to cause substantial defoliation and reduce weed vigor in some parts of Virginia. Palmer amaranth emerges later than many summer-annual weeds and continues to emerge throughout the growing season. Texas. Smooth pigweed (Amaranthus hybridusL.) However, it usually does not control the weeds, and occasionally feeds on some vegetable seedlings. Virginia. The weeds grow in disturbed areas, along roadsides and at the edge of developed areas. Carelessweed is often called pigweed because swine relish it. Upright pigweeds grow 3 to 10 feet tall. 4). Growth is related to cumulative Growing Degree Days, with a base temperature of 50 °F (Shrestha and Swanton, 2007; Horak and Loughin, 2000); thus, pigweeds grow much faster in hot climates than in northern regions with cooler summers. Viral pathogens such as cucumber mosaic virus and tomato spotted wilt virus can also be transmitted from pigweeds (Mohler and DiTommaso, unpublished). In the event that a heavy pigweed seed rain occurs, some weed scientists recommend inversion tillage to move seeds to a depth from which they cannot emerge (Mohler and Di Tommaso, unpublished). A single large plant can mature 100,000–600,000 seeds, and populations of 0.1–1 plants per square foot can shed 10,000–45,000 seeds per square foot, or 0.4–2 billion per acre (Massinga et al., 2001; Sellers et al., 2003). The amaranth flea beetle (Disonycha glabrata) occurs throughout much of the United States (Tisler, 1990), feeds on pigweed foliage (Fig. Egley, G. H. 1986. 2007. grow in wet, poorly drained soil. Quackgrass (Elytrigia repens) Quackgrass is a creeping, persistent perennial grass that reproduces … 1994. Manage Weeds on Your Farm: a Guide to Ecological Strategies. However, the prostrate pigweed (A. graecizans) grows close to the ground and has smaller leaves. To cook, add to boiling water and simmer uncovered for 25 to 30 minutes. More deeply buried seeds remain dormant and viable for several years, and germinate when brought to the surface by tillage or cultivation. 1), significant variation can occur within a species, and interspecific hybrids occasionally occur (Sellers et al., 2003). First cut off the entire flower head and put in a paper or fine mesh bag, and then let them dry for a week or two in a well-ventilated, shady area, like open-air barn. Pigweed that emerges after a crop's minimum weed-free period may not reduce the crop's yield, but it should be pulled or cut before flowering to prevent formation of mature seeds. Weed Science 49: 230–235. Figure 2. Amaranth also has a propensity to accumulate nitrates and oxalates, which can make it unpalatable and unsafe for eating, especially when it grows in soil that's been over-exposed to nitrates from commercial fertilizer. In Florida, cowpea, sunnhemp, or velvetbean cover crops seeded at high rates reduced but did not eliminate smooth pigweed growth (Collins et al., 2008). Figure 4. Spiny amaranth (left) and smooth pigweed (right) in bloom. 1996. Temperature effects on germination of nine, Steckel, L. E., C. L. Sprague, E. W. Stoller, L. M. Wax, and F. W. Simmons. Pigweeds are major weeds of warm season vegetables (Webster, 2006) and row crops (Sellers et al., 2003). It has several common names, including carelessweed, dioecious amaranth, Palmer's amaranth, Palmer amaranth, and Palmer's pigweed. Webster, T. M. 2006. 1983. All listed plants are found in central-east Canada and north-east United States (zones 4-7), but do grow elsewhere. Of course the wickedly thorny variety is what usually volunteers in my beds. Season-long competition by Palmer amaranth at 2.5 plants per foot of row can reduce soybean yield by as much as 79 percent. "Palmer amaranth does not play around,” Norsworthy adds. Rye residues contribute weed suppression in no-tillage cropping systems. However, rapid stem elongation allows pigweeds to escape shading in many cropping situations. Palmer amaranth emerges later than many summer-annual weeds and continues to emerge throughout the growing season. Find out which weeds grow where you live. Pigweed plants can grow to over six feet high with alternating oval to diamond-shaped leaves that may be up to six inches long. Always check with your organic certification agency before adopting new practices or using new materials. Because flaming usually does not kill grass weed seedlings, it is not recommended where grasses make up a significant portion of the weed flora. Fragile fern (Cystopteris fragilis) grows in near-neutral, dry conditions. Unpublished. Two pigweed species, tentatively identified as Palmer amaranth (left) and smooth pigweed (right), grow at the edge of a plastic mulched bed in organic vegetable production in Clemson, South Carolina. Palmer amaranth (, Knezevic, S. Z., S. F. Weise, and C. J. Swanton. and goldenrod (Solidago spp.) Pigweed is herbaceous plant that belongs to the amaranth family. Not really. Figure 11 Cultivation left a dust mulch around these young squash plants, thereby discouraging germination of pigweed and other small-seeded weeds. For example, seed germination responses show adaptive changes to different crop rotations (Brainard et al., 2007), and widespread herbicide resistance has been reported in several species (Fugate, 2009; Volenberg et al., 2007). Awesome, I'm glad it was helpful! Subsurface drip lines can provide moisture to the crop and leave the soil surface dry, thereby minimizing within-row weed emergence. According to the CalFlora website (, 21 species of amaranths occur (to some extent) in California. What is Amaranth? Because the small seeds have minimal nutrient reserves, pigweed seedlings are initially more dependent on readily available nutrients from the soil, especially phosphorus (P) and potassium (K), than larger-seeded plants such as corn, beans, and cucurbits (Hoveland et al., 1976; Mohler, 1996). However, crop competition may not control pigweeds, because of their shade-avoidance response and ability to break through the crop canopy through rapid stem elongation. Cook young tender pigweed leaves as you would spinach; steam or sauté/stir-fry in butter or oil. Let’s take a closer look at how pigweed is spread, and ways to resist pigweed’s growing chokehold on American farmland. Most amaranths make nutritious green vegetables or grain crops, and deliberate planting for food has helped some weedy species spread around the world. If pigweed plants have already formed seed, note that many of the seeds will stay in the head until winter.