Buddleja stachyoides Chamisso & Schlechtendal × B. tubiflora Bentham. Shrub up to 2–5 m tall, upright and open habit. Branchlets quadrangular, tomentose. Leaves opposite, sessile, ovate to lanceolate, 5–20 × 2–7.5 cm, apex acute to acuminate, base conate-perfoliate, margin crenate to dentate, upper surface with tomentulose trichomes, underside tomentose. Inflorescence spicate up 38 cm long, with 10–20 axillary cymes subtended by progressively smaller leaves towards the apex, each cyme averaging 15–24 flowers; flowers hermaphrodite, sessile; calyx tubular, tomentose, 6.5 mm long; corolla tubular, orange, tube 15 mm long, lobes 3 mm long. Stamens sessile, inserted near sinus. Ovary ovoid, tomentose. Capsule ovoid, 6 × 4 mm. Seeds dark brown, oblong, 0.5 × 0.25 mm. (Lindstrom, Dunn & Renfro 2009; pers. obs.).
USDA Hardiness Zone 7b-10
RHS Hardiness Rating H3
Buddleja ‘Orange Sceptre’ is a hybrid bred at the University of Arkansas (USA) by John Lindstrom and his team, from a breeding programme started in 1999. The parents are B. stachyoides, a South American species with a wide range, and B. tubiflora, a similar species with a more restricted range but more familiar to horticulture, albeit only as a greenhouse or conservatory specimen plant – neither parent is discussed in this work. This was not the first such cross, with Norman (2000) reporting both an in situ hybrid of these species in Argentina and ex situ hybrids made as early as 1934.
‘Orange Sceptre’ is a vigorous plant with large felted leaves and hirsute angled stems. The inflorescences are upright and long, with paired clusters of flowers at the axils of leafy bracts. All parts of the flower are tomentose. The colour is intermediate between the dark orange of B. tubiflora and the yellow-orange of B. stachyoides. Overall, the plant resembles B. stachyoides more than B. tubiflora. Both parent species are hermaphrodite, unlike the majority of Buddlejas from the Americas, which are dioecious. ‘Orange Sceptre’ is also hermaphrodite, and additionally highly self-fertile, coming more or less true from seed (pers. obs.).
Although bred as greenhouse specimen or conservatory plant, ‘Orange Sceptre’ proved to be hardier than either parent species. Reportedly hardy to USDA zone 7b, it will be cut back hard by frost but will grow back in the manner of a herbaceous perennial. When grown under cover, it will flower in all but the darkest winter months. However, grown outside in temperate regions, it will mostly flower late in the summer once it has had a chance to put on sufficient growth (Lindstrom, Dunn & Renfro 2009).
Originally only available in the USA, it has been recently introduced into the UK and France.