Binomial Name: (Amaranthus retroflexus)
Pigweed is a broadleaf summer in the family “Amaranthaceae” and the Genus”Amaranthus". It grows on a variety of soil textures and types. However, its prevalence on nitrogen-rich soils is more profound where it survives the pH ranges between 5.2 to 8.5 and evades growing in highly acidic soils. Besides cultivated lands, Pigweed is also a predominant weed in wastelands, garden beds, roadsides, riverbanks, and landscapes. Pigweed is a very competitive and aggressive weed that causes considerable yield loss in vegetables and orchards besides suppressing turfgrass in different Hardiness Zones in the US. It can also survive elevations up to 8500 feet above sea level. Pigweed is also a natural riverbank dweller of the milder and moist regions of eastern North America.
Origin and Distribution
Pigweed is native to Central and Eastern North America and exists throughout the US But, rare in highly acid soils with a pH below 5 in southeastern states. It has also naturalized throughout the temperate regions of the northern and southern US except for a few exceptions. It grows vigorously in the western United States, Northern Mexico and is also native to the Cordillera of Central and South America. At present, Pigweed has developed itself a troublesome, invasive, and widespread weed in eastern North America in croplands, garden beds, orchards, and landscapes.
Pigweed-Identification
Pigweed is a low-maintenance and rapidly growing erect plant that reaches up to 10 feet tall within one growing year when neglected. The leaves in the upper portion of the stem are relatively small. Leaf base is often rounded with a tip that can be acute, rounded, obtuse, or emarginated. The upper sides of the leaves are non-hairy whereas, the undersides of the leaves contain reddish or purple hair. The size of the leaves varies between 4 to 6 inches. A single plant may have both male and female flowers. The flower inflorescence is large having, dense flowery clusters interposed with spikey green bracts. The fruit is about 1/13th of an inch containing a tiny black seed. Whereas, a mature Pigweed plant can produce almost 117,000 seeds.
Pigweed-Propagation and Lifecycle
The pollination in Pigweed often takes place through wind and to some extend by pollinators like birds, bees, and insects. However, Insect pests often don't infest Pigweed, and the same is true for bacterial plant diseases. Pigweed grows indeterminately and initiates elongated inflorescences from the lateral leaf axils. If the terminal panicle is disturbed or damaged. During a severe disturbance, they may adopt an almost horizontal growth form. The spiny-tipped bracts protect the seeds from predators. The light, tiny, and slightly flattened seeds disperse through the wind that can overwinter under plant debris or below the soil surface. The germination from the seeds takes place when the temperature is favorable, usually between 75 to 100°F.
Fun Facts About Pigweed
Pigweed-Prevention and Control
Cultural Control
Hoeing and hand pulling Pigweed is the best practice that gardeners can adapt well at the start of spring. Hand pulling a small weed is easy during the 4 or 5 leaf stage before Pigweed sets flower. Pigweed can also be controlled by using sawdust, shredded leaves, plant debris, and grass clippings for organic gardening. A similar practice is helpful for turfgrasses but, Mowing the lawns before Pigweed prepares to flower is most beneficial. Also, fertilize lawns with high Nitrogen and Potash nutrients and follow Mowing after that immediately. It will add to the beauty of turfgrasses besides offering them the vigor to suppress all weeds that could potentially harm them.
Chemical Control
Control using Pre-Emergent Herbicide
Monterey Weed Stopper II
Weed Stopper contains 43% Trifluralin which stops Pigweed seeds to germinate if they're still on the soil surface and viable. Weed Stopper needs to irrigate a field or the garden once you apply. Avoid spraying on the foliage of vegetables and fruits that are actively growing. Although it’s not recommended for turfgrasses, it has proved to be a prospective herbicide without any stress if applied before seeding warm-season turfgrasses. Additionally, it provides long control and doesn't allow Pigweed seeds to germinate within 5 months of its application.
- Monterey Weed Stopper II With Trifluralin 32oz A pre-emergence herbicide for the control of grasses and broadleaf weeds in vegetables, trees, shrubs, flowers, roses, rock gardens, and groundcovers
- Delivers up to 5 months of control
- Apply to the soil surface and water in
Add 1.5 ounces in one gallon of water to spray on 500 square feet of the targeted area.
Control using Post-Emergent Herbicides
Weed Beater Complete
Weed Beater contains both Prodiamine (0.2%) and Sulfentrazone (0.1%) in a readymade granule formulation that absorbs from the Pigweed foliage and roots. Weed Beater is both a Pre-emergent and Post-emergent herbicide that stops germination from the seeds in a broad range of broadleaf weeds and grasses. It burns the weeds which are actively growing in turfgrasses. Weed Beater requires supplemental irrigation within 24 hours of its application. Its granular formation is easy to spread that triggers the mode of action of both ingredients.
- 5,200 SQUARE FEET OF PROTECTION - With just 10 pounds of Weed Beater Complete, you can protect up to 5,200 square feet of your property.
- PRE AND POST FORMULA - The formula for Weed Beater Complete takes care of pre-emerging and post-emerging control of both grassy and broadleaf weeds.
- WIDE RANGE OF CONTROL - This product gets rid of crabgrass, nutsedge, goosegrass, ground ivy, and way more. It can kill the toughest weeds with systemic action from the leaves all the way down to the root.
10-pound granules are applied over 5200 square feet of turfgrasses.
Scotts Turf Builder
A fertilizer and herbicide combination that not only burns Pigweed and other broadleaf weeds but supplements your turfgrasses with much-needed fertilizers like nitrogen and Potash. NPK ratio in the formulation remains 28-0-6 which, means 28% Nitrogen, 0% Phosphorus, and 6% Potash. 1.21% of 2,4-D and 0.61% of Mecoprop-P are excellent to burn the foliage within 3 to 4 days of application. Such types of combinations are fit to apply in early spring and again in the autumn when turfgrasses prepare for overwintering.
- Improved formula—up to 2X more powerful dandelion and clover control
- Clears out dandelions and clover—satisfaction guaranteed
- Weedgrip Technology grips the weeds you see—and the ones you don't
One pound of Scotts Turf Builder is sufficient to apply between 300 to 350 square feet area of Pigweed infested turfgrasses.
Scotts Weed Control
Another weedicide from the same supplier lacks fertilizers. In addition, it combines an additional herbicide, and the overall mix makes it ideal for controlling all sorts of broadleaf weeds including, Pigweed. It contains 2,4-D, Mecoprop-p, and Dicamba in a ratio of 1.10%, 0.167%, and 0.071%, respectively. Additionally, this chemistry is available in a ready-to-apply formulation and application suit good when weeds grow actively in the turfgrasses.
- Kills even the toughest weeds, like dandelion and clover
- Specially formulated to control more than 200 weed types
- Starts working on contact
Try to keep the lawn wet before applying Scotts Weed Control pack on 5000 square feet area of turfgrasses.
Learn How to control and get rid of other weeds in our complete Yard Weeding Guide.