The species Coreopsis grandiflora, also known as Tickseed Coreopsis, is favored in the plant world for its versatility. It can grow in dry soil or moist, fertile soil, but according to professor Andy Pulte of UT's Plant Sciences department, the real key to its success is dry soil. It can grow in partial shade, but prefers full sun. Its golden flowers grace the garden from April until August. Although Tickseed Coreopsis may be susceptible to several diseases and insects such as leaf spot or the potato aphid, it is rarely affected.
In 2007, a cultivar of Coreopsis grandiflora by the name of 'Presto' was tested as an annual trial by the 34 All-America Selections trial sites -- including the University of Tennessee Gardens located in Knoxville and Jackson. 'Presto' went on to win gold that year from Flueroselect which is based across North America and Europe. So what's so great about this cultivar? Unlike regular Tickseed Coreopsis which can grow up to three feet tall, 'Presto' is naturally compact. One clump can produce many double-petaled flowers, even in its first year.
So, if you are planning a flower bed on a difficult site, and you need a compact clump of golden flowers, Presto! look no further because Coreopsis grandiflora 'Presto' is the perfect plant for the job.
UT Gardens 2007 Annual Trial Results
Fleuroselect: the International Organisation for the Ornamental Plants Industry
Thompson and Morgan Seed Company
Manual of Herbaceous Ornamental Plants by Steven Stills