Coreopsis grandiflora, or Pot of Gold, is a perennial form of Coreopsis that has very showy flowers. The compact plants only reach 24 inches (60 cm) tall and wide. Lanceolate leaves are up to 4 inches (10 cm) long by 1 inch (2.5 cm) wide and medium to dark green. This is the third year for me to grow these plants and I am still impressed with them. They are very easy to grow in containers or in the landscape. Plants are hardy in USDA zones 4-9. In the more northern zones they can be treated as annuals.
Blooming: In the greenhouse, the plants in containers will start blooming in June. They will bloom all summer long with showy 2 inch (5 cm) across semi-double heads. In the landscape here in Oklahoma they will bloom from mid June through mid October.
Culture: Coreopsis grandiflora need full sun to light shade with a well drained soil mix for containers. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 2 parts loam to 1 part sand or perlite. The plants are well watered and allowed to dry before watering again. We fertilize them monthly with a balanced fertilizer. In the landscape, the plant need a well drained soil, but the plants are very drought tolerant. In my yard, I will water them once a week in periods of low rainfall, and I only fertilize them once during the growing season. In late October in the landscape, we cut the plants back to ground level and mulch them well for the winter. In containers in the greenhouse, containers are moved to the cool rooms for over wintering. As plants die back, they are cut back to pot level and water is restricted to once a month, with no fertilizer added during this period.
Propagation: Coreopsis grandiflora is best propagated from seed. Seed germinate readily at 70° F (21° C). Plants will bloom in 11-12 weeks from seed.
Coreopsis grandiflora was featured as Plant of the Week June 6-12, 2008.
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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. ©1998-2012 All rights reserved.