Indian Corn Cob, Corn Cob Plant, Corncob Euphorbia, Corncob Cactus
Synonyms of Euphorbia mammillaris: Euphorbia enneagona Haw., Euphorbia erosa Willd., Euphorbia fimbriata Scop., Euphorbia latimammillaris Croizat, Euphorbia platymammillaris Croizat, Euphorbia scopoliana Steud., Treisia erosa (Willd.) Haw., Vallaris fimbriata (Scop.) Raf.
Euphorbia mammillaris L. is the correct and accepted scientific name for this species of Euphorbia. It was named and described as such by Carl von Linnaeus in the first edition of Species Plantarum in 1753.
Carl Linnaeus is also credited with naming the Euphorbia genus and describing it in the first edition of Species Plantarum in 1753. Plants of the World Online currently still lists 1,986 accepted species in the Euphorbia genus (as of 11-3-19 when I am updating this page). Those numbers could change.
I picked up this Euphorbia mammillaris cutting on March 29, 2019. I have had a few other Euphorbia species as companions and we have always gotten along very good. I like the small leaves and there are remnants of its small yellow flowers.
Origin: South Africa
Zones: USDA Zones 8b-11 (15-40° F)
Size: 6-18” or “more” tall. HMMM…
Light: Sun to part shade
*Soil: Very well-draining soil. Potting soil amended with additional pumice or chicken grit and perlite.
Water: Regular watering during the summer. Very little, if any, during the winter.
*There are a lot of potting soil recipes online and many people develop their own with experience and what is readily available. Read the ingredients on the bag and always start with a base of a reliable brand name. I always use either Miracle Grow or Schultz Potting soil because I can buy it in large bags. They also offer cactus soil in smaller bags with similar ingredients. I used 2 parts potting soil with 1 part additional pumice and 1 part chicken grit. After reading that cactus and succulent enthusiasts were recommending pumice in place of perlite and grit, I decided to try. So, since late in 2018 I purchased a bag of pumice online from General Pumice. I have been using a combination of about 50% potting soil and 50% pumice with favorable results. Many cactus and succulent enthusiasts do not recommend potting soil with a lot of peat, but other potting soils I have experimented with gave me unsatisfactory results.
This species has 7-17 ribs with hexagonal tubercles in vertical rows resembling an ear of corn. It also has a few spines. The tubercles swell with normal watering and shrink during dry periods.
There is not much information online about the Euphorbia mammillaris for some reason. It is a very interesting plant in my opinion.
The Llifle (Encyclopedia of Living Forms) website has more than any other website about this species and growing recommendations.
Although most information online says this plant grows up to maybe 18″ tall, Llifle also says…
“…young plants are happy growing indoors, where they can easily reach the ceiling.”
“It is a moderately fast grower, and will quickly become large landscape masterpieces in just 3-5 years.”
SOOOO… It will be interesting to see what this plant does first hand.
Description: It is a short-stemmed dioecious shrublet producing a dense cluster.
Stem: Thick deep green,, erect, simple and ribbed, that in cultivated plants may branch above, 1, 5-6 cm in diameter.
Mature: Height 20-35 cm tall. Usually, there are many club-like lateral branches, starting about 10 cm and arches upward.
Ribs: 7-17, with hexagonal crowded tubercles set in vertical rows after the manner of an ear of corn and separated by horizontal groves.
Spines: Occasionally present and scattered, thick, blunt, and whitish, up to 1 cm long. The “spines” are the solitary sterile peduncles.
Leaves: Small, ephemeral (meaning they last for a short time).
Flowers: Produces yellow solitary cyathia at the top of each stem. Peduncle +/- 2 mm long with several bracts up to 3 mm long. Nectar glands elliptic, separate, yellow-green to purplish.
Blooming season: Late winter to early summer.
Fruits: Obtusely lobed, up to 6 mm in diameter, subsessile.
Remarks: Euphorbia fimbriata is similar to E. mammillaria but has conical stem tubercles.
I had to move the potted plants inside for the winter on October 11 (2019) because an “F” was in the forecast. As always, I photograph and measure the cactus and most of the succulents. The Euphorbia mammillaris measured 5 3/4″ tall. I didn’t measure it when I first put in the potting soil so I have nothing to compare it to. I do know it is growing, though.
There are a lot of leaves on the upper part of the stem which will fall off at some point. Their leaves are ephemeral which means they only last for a period of time but they will regrow when the time is right. That makes it interesting to grow this plant.
I am kind of running out of words to say…
Oh, the spines… It does have a few spines toward the base of the plant and side branches.
I had to bring the plants inside for the winter on 10-15-20 because an “F” was in the forecast. As always I took photos and measurements. The main stem of the Euphorbia mammillaris measured 8″ tall so it is doing quite well.
I really like the combination of leaves and thorns.
I will continue to add more photos and information as time goes by.
Be sure to click on the links below for further information about growing this plant. Llifle has a lot of good information. There is also a variegated form of this species.
I hope you enjoyed this page and maybe found it useful. If you have any comments, questions or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.