Seed Source Affects Flowering and Growth of Container-Grown Black-Eyed Susan (Rudbeckia hirta L.)

Abstract

Abstract Rudbeckia hirta, black-eyed susan, is a popular container-produced native wildflower. However, there is a growing demand for regionally adapted selections because of ecological and sustainability issues. In separate studies in 2001 and 2002, seed from three sources — north Florida (NFL), central Florida (CFL), and Texas (TEX)—were sown in the greenhouse in mid-January. Seedlings were transplanted to cell packs in early February. In early April, liners were potted in 2.5 liter (0.66 gal) containers and placed on an outdoor production bed under full sun. Full bloom occurred about 21.5 to 23 weeks after sowing. TEX achieved full bloom 10 days earlier than NFL or CFL. Except for CFL in 2001, most plants were of a commercially acceptable height. The most uniform growth or flowering trait based on coefficients of variation was date of full bloom, with date of first bloom just slightly more variable. Other growth and flowering traits were moderately to highly variable.