E. milii is a woody,
succulent subshrub or
shrub growing up to tall, depending on
cultivar, with densely spiny stems. Some varieties grow in a more horizontal, sprawling, or prostrate manner, while others grow nearly vertically. Certain cultivars are prized for their thinner stems, while many, especially the Thai hybrids, have considerably thicker, substantial stems, measuring several inches in diameter. Just as the flowers and growth habit can vary by cultivar, so too can the sharpness/bluntness or shape and consistency of the spines. On most varieties, the spines will measure up to long, and aid the plant in scrambling over other plants, eventually forming a dense and impenetrable wall. The fleshy, green
leaves are found mainly on new growth, The plant thrives between spring and summer but produces flowers all year round.
Extrafloral nectaries at the involucre were first reported on
E. milii by Teng and Hu 2002. ==Toxicity==