Irrigation frequency affects growth of sweet viburnum during landscape establishment in three hardiness zones. 2009. Shober, A.L., K.A. Moore, C. Wiese, S.M. Scheiber, E.F. Gilman, M. Paz, M.M. Brennan, and S. Vyapari. HortScience. In Review.

The survival and quality of shrubs planted in the landscape from containers is dependent on irrigation to ensure the development of a healthy root system. This study determined the effect of irrigation frequency on survival, quality, canopy growth index, root to canopy spread ratio, and dry root and shoot biomass of Viburnum odoratissimum Ker-Gawl. (viburnum) planted in Florida in USDA hardiness zones 8b (Citra, FL), 9a (Balm, FL), and 10b (Fort Lauderdale, FL). Viburnum shrubs were planted into the landscape from 11.4 L (#3) containers and irrigated with 3 L every 2, 4, or 8 days. Shrubs were planted on eight dates over a two year period (2004 to 2006). Irrigation frequency during the 22 week irrigation period had no significant effect on viburnum survival or aesthetic quality at any location. Plant growth index, root spread and harvested biomass were all influenced by irrigation frequency at one or more locations in Florida. Based on results, we suggest that viburnum can be mostly established by 22 weeks after planting (WAP) by supplementing natural rainfall with 3 L per irrigation event to the root ball of the plant at a frequency of every 8 days in zones 8b and 9a and every 4 d in zone 10b. However, more frequent irrigation may be needed in order to achieve optimal canopy growth of viburnum, especially during times of drought.