Common Name: blood flower
Type: Herbaceous perennial
Native Range: South America
Zone: 9 to 11
Height: 2.00 to 3.00 feet
Spread: 1.50 to 2.00 feet
Bloom Time: June to October
Bloom Description: Red-orange with yellow hood
Sun: Full sun
Suggested Use: Annual
Attracts: Hummingbirds, Butterflies
Blood flower is winter hardy to USDA Zones 9-11. In St. Louis, it is grown as an annual. It is easily grown from seed each year. Start seed indoors in pots 8-10 weeks before last spring frost date. Plant seedlings outside after last frost date. Grows best in light, rich, evenly moist, well-drained soil in full sun. Tolerates some light shade. Tolerates some soil dryness. Plants are noted for being weedy in their native tropical habitats and in warm winter areas such as the deep South where they will self-seed somewhat profusely. Plants will not self-seed in the St. Louis climate. Container plants may be cut back and brought inside into bright sunny locations in winter. May also be grown as an indoor plant in bright sun with regular watering during the growing season and with reduced watering in a cool location in winter.
Blood flower is a tender evergreen perennial in the dogbane and milkweed family. It is native to South America, but has naturalized worldwide in many tropical and subtropical areas. It has a much longer flowering period than the perennial milkweeds that are winter hardy in St. Louis. It typically grows as a subshrub to 2-3’ tall on upright stems clad with pointed, opposite, lanceolate leaves (to 6” long). Leaves are medium green sometimes with white midribs. Showy flowers with five sepals and five lobes appear in rounded axillary clusters (cymes) in late spring to early summer. Flowers are red-orange with yellow hoods. Flowering continues throughout the summer to early autumn. Hummingbirds, butterflies and bees are attracted to the flowers. Monarch butterflies lay eggs on this plant and the resulting larvae (caterpillars) use the plant leaves as a food source. Flowers are followed by long, narrow seed pods (3-4” long) which split open when ripe releasing silky tailed seeds for dispersal by wind. Stems and leaves exude a milky sap when cut or bruised. Plants can be poisonous to livestock. Additional common names for this plant include tropical milkweed, scarlet milkweed, swallow wort, Indian root and matal. Asklepios is the Greek god of healing.
No serious insect or disease problems. Somewhat weedy and can spread in warm winter locations where it will self-seed. Watch for aphids. Sooty mold may develop if aphid populations are not checked. Consider wearing gloves when working with these plants because the milky sap is poisonous if ingested and can be toxic to human skin.
Attractive foliage and flowers for beds, borders, cottage gardens, meadows and butterfly gardens. Also a good cut flower. Dried seed pods are attractive in arrangements.