in J. Lamarck et al., Encycl. 1: 513. 1785. (as Budleia)
Shrubs, climbing, sarmentose, 20–50 dm. Stems branched, tomentose. Leaves often with globular stipular lines; petiole 5–15 mm; blade ovate to elliptic, 8–15 × 2–5 cm, base rounded, margins entire, apex acuminate, abaxial surface tomentose, adaxial glabrous or glabrate. Inflorescences terminal, tapering-spicate thyrses, 5–25 × 3–5 cm, cymes 10–25 pairs, 5–15-flowered. Pedicels essentially absent; bracteoles present. Flowers slightly fragrant; calyx tomentose externally, tube 2–3 mm, lobes 0.5–1 mm; corolla yellowish orange, salverform, tube 7–9 mm, lobes suborbiculate, 2.5–3.5 × 2–3 mm; stamens inserted proximal to throat of corolla tube, included in tube; ovary subglobular, 1–1.5 mm, tomentose at tip; stigma clavate, 1–1.5 mm. Fruits berries, bluish purple, globular, 2.5–5 × 2.5–5 mm, papillose, indehiscent. Seeds ovoid, 0.6–0.9 × 0.5–0.6 mm, wings absent. 2n = 38.
Phenology: Flowering Mar–May; fruiting not known in continental United States.
Elevation: 10–20 m.
Introduced; Fla., Indian Ocean Islands (Madagascar), introduced also in Mexico, West Indies (Cuba, Puerto Rico), South America (Argentina, Uruguay), Europe (Greece), Africa (Republic of South Africa), Indian Ocean Islands (Mauritius, Réunion), Pacific Islands (Fiji, Hawaii, New Caledonia, New Zealand), Australia.
Buddleja madagascariensis is considered a serious invader in Hawaii at 900–1200 m, where it sets abundant fruits (Hawaii Invasive Species Council, https://dlnr.hawaii.gov/hisc/info/species/smoke-bush/); this contrasts with the report by A. J. M. Leeuwenberg (1979) that he had observed specimens with fruits only from Crete, Madagascar, and Mauritius.