Evaluation of 14 butterfly bush taxa grown in western and southern Florida: II. Seed production and germination

Abstract

Because of its weedy nature, extensive use in the landscape, numerous cultivars, and history as an invasive plant in other countries, butterfly bush (Buddleja) was an appropriate candidate to evaluate for seed production and germination in Florida. Seed production was quantified for 14 butterfly bush taxa planted in western Florida (Milton) and central southern Florida (Fort Pierce). Each of the 14 taxa evaluated produced seed. In Fort Pierce, japanese butterfly bush (B. japonica) had the greatest capsule weight and 'Gloster' butterfly bush (B. lindleyana) had the second greatest capsule weight as compared to other taxa. In Milton, 'Gloster' had the greatest capsule weight and japanese butterfly bush and 'Nanho Alba' butterfly bush (B. davidii var. nanhoensis) had the second greatest capsule weights as compared to other taxa. The shape and number of seed capsules per infructescence varied with cultivar. Seeds were cleaned and germinated in germination boxes with and without light at 20/10, 25/15, 30/20 and 35/25°C (68.0/50.0, 77.0/59.0, 86.0/68.0 and 95.0/77.0 °F). Regardless of temperature or cultivar, light was required for germination. At each temperature, 'Nanho Blue' butterfly bush (B. davidii var. nanhoensis) and 'Moonlight' butterfly bush (B. x weyeriana) had highest germination rates (63-74%) as compared to other taxa.