Rudbeckia hirta, or Gloriosa Daisy, is a hairy, nonrhizomatous biennial or short lived perennial that is sometimes grown as an annual. It is a very conspicuous native of Midwestern United States grasslands. It is a very coarse plant with hairy obovate to lanceolate leaves up to 6 inches (15 cm) long by 2.5 inches (6.35 cm) wide. Plants will reach 2-3 feet (0.6-0.9 m) tall and wide. A very attractive plant, it is also very drought tolerant. They make excellent container plants and are hardy from USDA zones 3-11.
Blooming: Plants grown from seed will bloom in their first year. If planted in containers, they will bloom nonstop from early summer to fall. The 4-6 inch yellow, orange and mahogany flowers are very showy and make very good cut flowers.
Culture: Rudbeckia hirta need full sun to partial shade, with a well drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part peat moss to equal parts of loam and sand. The plants are well watered and allowed to dry slightly before watering again. We fertilize plants grown in containers on a monthly basis with a balanced fertilizer. If grown in the landscape, they are more drought tolerant, but perform better with regular watering and fertilization. The plant can become weedy in the landscape, and flower heads should be removed if you don’t want too many volunteers coming up the following year. This also helps in keeping robust looking flowers on the plant. In the greenhouse, we collect seed from plants in the fall and discard the plants.
Propagation: Rudbeckia hirta is best propagated from seed. Seed should be surface sown and will germinate in 5-10 days from sowing.
Rudbeckia hirta was featured as Plant of the Week January 9-15, 2009.
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Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2017 All rights reserved.