Herbacea is a small tree or low shrub; as a tree it may reach 16 feet in height, but typically is much shorter. It has smooth light gray bark and often produces herbaceous stems from a woody base. If temperatures drop below freezing, stems are killed back but resprout. The stems are covered in curved spines. Leaves are yellowish green in color, 6 -8 x 2 1/2 inches and composed of 3 arrow-head shaped leaflets, each 1 - 3 inches long. Flowers are a vivid scarlet color, borne on tubes about 2 inches long, arranged in clusters, each bloom is 1 1/2 - 2 1 /2 inches long; flowering extends over about 3 months in spring-summer. Hummingbirds and butterflies are attracted to the flowers. Fruits are woody pods, 2 - 4 inches long, with short beaks, containing bright red seeds with a black spot, splitting open when mature. All parts of the plants are poisonous, containing toxic alkaloids. Seeds are used for propagation and as a rat poison; tip cuttings can be used for propagation. Extracts of roots, leaves and seeds are used in traditional medicine. Herbacea in cultivation is a hardy plant, needing adequate moisture but well-drained soils. As a tree or shrub it requires pruning, avoiding direct contact with the milky sap. In landscaping, herbacea is low maintenance, in tree or shrub form it is a good source of spring color from the vibrant blooms, in a garden, park or patio.