Euphorbia polygona var. minor (Dwarf African Milk Barrel) - A small clustering cactus-like Euphorbia with primary cylindrical stems to 1 to 2inches thick by up to 6 inches tall of unequal length that radiate up and outwards from the center of the plant with ridges of tubercules running vertically that are lined with spine like peduncles (persistent flower stalks) protruding from each tubercle axil. The cyathia, as the unique flowering inflorescences of a Euphorbia are known as, appear at the stem tips at the axil of the tubercle with individual cyathium having a cup ringed by five green glands - the species is dioecious, and our plants are male with no fruit produced.
Plant in full to part sun in a well-drained soil. Cold hardy down to at least short duration temperatures to 25 °F. A great small plant for a crevice in the succulent garden or as a container specimen. Because of its spine-like peduncles this plant resembles but is unrelated to cactus.
Euphorbia polygona is native to the Eastern Cape of Southern Africa from Uitenhage to Albany and while dominant in rocky quartzite fields, it is not restricted to them. There has long been confusion between whether this species should be called Euphorbia polygona or Euphorbia horrida and plants in this group are often referred to as being in the "polygona complex". Though now considered conspecific (the same species) with the valid name Euphorbia polygona, there are differences between the plant cultivated under one name or the other with the typical Euphorbia polygona having more uniform gray stems covered along the ridges with the woody spine-like peduncles but few actual spines and having dark reddish purple flower-like glands in the cyathia, while the plant known as Euphorbia horrida has more irregular stems held in more open clumps and often white striped with greenish-yellow glands in the cyathium and often more actual spines subtending them. Current treatment of this species includes 12 varieties to cover all the different variants found in the polygona complex.
Our plants are from cuttings taken off a large container specimen received with the plant collection of Stockton, California succulent grower Alice Waidhofer in 2005. Alice was meticulous with her labeling but we seemed to have lost the label on this plant so we do not know Alice's source our whether the name Euphorbia polygona var. minor is valid for this plant. Others we have consulted with agree that it looks like it belongs in the "polygona complex" but other species we have considered include Euphorbia aggregata, Euphorbia frankie, Euphorbia cereiformis and Euphorbia submamillaris. If anyone have a good idea on the identity of this attractive smaller clustering Euphorbia, we would love to hear about it.
The information about Euphorbia polygona var. minor displayed on this web page is based on our research conducted in the nursery's horticultural library and from reliable online resources. We also include observations made about it as it grows in our nursery gardens and other gardens we have visited, as well how the crops have performed in containers in our nursery field. We will also incorporate comments we receive from others and welcome hearing from anyone with additional information, particularly if they can share cultural information that would aid others in growing this plant. |