Amaranthus spinosus-Spiny Amaranth, Spiny Pigweed

Amaranthus spinosus (Spiny Amaranth) on 9-8-18, #504-2.

Spiny Amaranth, Spiny Pigweed, Thorny Pigweed, Needle Burr

Amaranthus spinosus

am-uh-RANTH-us  spy-NO-sus

Synonyms of Amaranthus spinosusAmaranthus caracasanus Kunth, Amaranthus coracanus Mart., Amaranthus diacanthus Raf., Amaranthus spinosus f. inermis Lauterb. & K.Schum., Amaranthus spinosus var. basiscissus Thell., Amaranthus spinosus var. circumscissus Thell., Amaranthus spinosus var. indehiscens Thell., Amaranthus spinosus var. purpurascens Moq., Amaranthus spinosus var. pygmaeus Hassk., Amaranthus spinosus var. rubricaulis Hassk., Amaranthus spinosus var. viridicaulis Hassk., Galliaria spitosa (L.) Nieuwl. 

Amaranthus spinous L. is the correct and accepted scientific name for this species of Amaranthus. The genus and species were described by Carl von Linnaeus in the second edition of Species Plantarum in 1753.

According to Plants of the World Online by Kew, there are still 95 accepted species in the Amaranthus genus (as of 1-12-20 when I am updating this page). That number can change as plants get reclassified.


Distribution map of Amaranthus spinosus from Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; Retrieved on 1-12-20.

As you can tell by the above distribution map provided by Pants of the World Online, Amaranthus spinosus are found in much of the world. Locations in green are where the species is native and purple is where it has been introduced.


Amaranthus spinosus (Spiny Amaranth) on 9-8-18, #504-3.

Amaranthus spinosus is definitely one of those plants you love to hate. I remember my grandpa digging them on here on the farm when I was a kid. There are several weeds that it is nearly impossible to eliminate and this is one of them. They are a never-ending battle because not only do they produce a lot of seed (around 100,000 per plant), but their seeds remain viable for many years. Their seeds need light to germinate, so tilling the soil is one good way to help control them. I don’t like this species growing anywhere on the farm, but I really don’t like them in the garden. I pull weeds by hand but that is hard to do with this plant because of their thorns.


Amaranthus spinosus (Spiny Amaranth) on 9-8-18, #504-4.

Once you have this plant in your garden or in your pastures, you will easily be able to recognize it. It is definitely not one that you will forget.


Amaranthus spinosus (Spiny Amaranth) on 6-24-19, #605-1.

Once you have it, you will be more concerned with getting rid of it. That is not easy to do because there are always more to come.


Amaranthus spinosus (Spiny Amaranth) on 6-24-19, #605-2.

Interesting that such a plant as this so detested by many is actually edible and eaten by many in some countries. It is very nutritious and has one of the highest concentrations of useable calcium. Even though it may be nutritious, I think I will not be eating any part of this plant.


Amaranthus spinosus (Spiny Amaranth), 6-24-19, #605-3.

Melody Rose has published an interesting article on Dave’s Garden you may be interested in reading.

Even though this plant is easily recognizable, many links below give detailed descriptions of their leaves stems, flowers, etc.

I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. I have grown over 500 different plants and most have pages listed on the right side of the blog. I am not an expert, botanist, or horticulturalist. I just like growing, photographing and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by the experts and provide much more information. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at I would enjoy hearing from you.