Dr. Bill Miller recently reported that research at Cornell University has shown that planting depth is a major factor in how well bare-root perennials perform. The research has found that planting bare-root crowns at or slightly above the soil surface results in much better growth and performance as compared to when crowns are planted below the soil surface. Deep-planted roots typically grow much more slowly and with less vigor.
Miller recommends growers carefully review-planting practices with crews and consider the effects of how container transportation and handling procedures after planting might affect final crown depth. The research was conducted with the support of the Royal Dutch Wholesalers’ Association for Flowerbulbs and Nursery Stock (KBGBB) in Hillegom, The Netherlands.
A full report of the results is available at the Flowerbulb Research Program Web site at www.flowerbulbs.cornell.edu , under “recent publications.” Additionally, there is a printable pictorial guide to several bare-root crowns and examples of proper planting depth, as determined by the research. Contact Bill Miller at firstname.lastname@example.org  for more information.