Effect of Incorporating Controlled-release Fertilizer on Adventitious Rooting and Growth of Artemisia, Gaura, and Nepeta

Abstract

Controlled-release fertilizer was incorporated into the rooting substrate to determine its effect on adventitious rooting and subsequent growth of three herbaceous perennials: Artemisia ludoviciana ‘Valerie Finnis,’ Gaura lindheimeri ‘Whirling Butterflies,’ and Nepeta x faassenii ‘Six Hills Giant.’ Nutrient treatments consisted of a control, and four treatments each of Nutricote ® 13–13–13 Type 180 and 18–6–8 Type 180 at 3, 6, 9, and 12 g/liter (5, 10, 15, and 20 lbs/cu yd) incorporated into the rooting substrate. These treatments equate to N rates of 0, 0.38, 0.77, 1.16, 1.54, 0.53, 1.07, 1.6, and 2.13 g/liter (N at 0, 0.65, 1.3, 1.95, 2.6, 0.9, 1.8, 2.7, and 3.6 lbs/cu yd), respectively. Incorporating controlled-release fertilizer into the rooting substrate at levels equal to or greater than 0.77 g/liter (1.3 lbs/cu yd) increased shoot dry weights, but had no effect on adventitious rooting and little influence on root number or root dry weight. This in turn influenced shoot:root ratios and potentially plant quality. There was no difference between the two formulations.