Euphorbia Milli Information
A native to Madagascar, is a succulent, with thick, fleshy stems adapted for water storage. The stems are 5-7 sided, greyish-brown, branched & up to 2-3' in height, with many prominent, grey 1" spines. The leaves tend to be obovate (wider near the tip), up to 1Ĺ” long, but much larger (to 6") in the Thai hybrids. They are spirally arranged, have smooth margins, & vary from bright green to grey-green. Foliage is present only on new growth. Euphorbia millii var splendens is similar, but grows to 5-6'.
The inflorescence is composed of a specialized structure termed a cyathium comprising a cup-like involucre, within which is set a single much reduced female flower surrounded by three male flowers reduced to single stamens. The cyathia are borne in clusters (cymes) and each cyathium is subtended by two colorful bracts. These are termed cyathophylls, and both red and yellow (in Euphorbia millii var lutea) occur naturally. Plants are in flower year round, but are at their best in dry, sunny weather (Winter & Spring). As with other euphorbs, Euphorbia millii produces copious quantities of poisonous, milky sap that can cause skin irritation, & contains tumor promoting chemicals (diterpene esters). The spines should be sufficient warning to handle with care.
Hybrid Euphorbia Millii
For the past 20 -30 years growers in Thailand have developed an array of hybrids with much larger flowers (i.e. the cyathophylls) than found in previous cultivars, with a seemingly infinite variety of color combinations. These range from all shades of red and pink to cream and yellow, often with blends of different colors. The subtle pastel shades of some cultivars are reminiscent of some “old fashioned” rose blooms, while the masses of cyathophylls packed together are reminiscent of hydrangeas. The color of the blooms of some cultivars can change as they develop. Sun and temperature also effect color, full sun to 30% shade being optimum.
Another attractive feature of these plants is their compact, upright form, as compared to the more leggy twisted growth of E. milii cultivars. These latter can become a tangle of unattractive stems if not carefully trained. Apart from having stout stems and a more attractive form, many of the Thai hybrids have far more handsome foliage, the leaves being larger and a brighter green.
In Thailand these plants are known as “poysean” (Chinese for eight saints) and are regarded as bringing good fortune (lucky plants). Though their exact lineage is uncertain, the formal botanical name E. x lomi Poysean Group has been proposed for this group of cultivars.
More than two thousand different cultivars have been developed in Thailand, most of these having local Thai names. Increasingly they are becoming available in the US, either with names
in English or simply designated by color. The first introductions to the US were from a Florida nursery as E. milii Super GrandiflorumTM. This name has no botanical standing, though it may be used by nurseries and in plant catalogs.
From : http://miami-dade.ifas.ufl.edu/programs/commorn/publications/crown-of-thorns-homeowner.PDF