Branching Enhancers, Configure (6-ba) and Augeo (dikegulac Sodium), Affect Branching of Herbaceous Perennials

We evaluated the branching response of established containerized perennials to spray or drench applications of Augeo (OHP, Inc.) applied during active growth as compared to Configure (Fine Americas, Inc.). Crops tested included Gaillardia ‘Gallo Yellow,’ Echinacea ‘Sombrero Hot Pink,’ and Phlox paniculata ‘Laura.’ Treatments were applied about 2 weeks after plugs were planted in 3.4-liter containers. Augeo was applied as a foliar spray at 0, 400, 800, 1600 or 3200 ppm or a drench (300 ml/pot) at 0, 40, 80 or 160 ppm. Configure was applied as a foliar spray at 600 ppm. Only Gaillardia had significant phytotoxicity with the Augeo treatments. However, the 400 ppm spray resulted in plants with twice as many branches as untreated controls with only minor and short term phytotoxicity. Configure also increased the number of branches on Gaillardia. Neither Augeo nor Configure consistently increased the number of shoots or lateral branches on Echinacea or Phlox. Although many crops are responsive to Augeo and/or Configure, there are cultivar and crop differences. INTRODUCTION Enhancement of plant branching improves plant architecture, tends to provide some growth regulation, improves pot fill and thereby may reduce crop time, may increase number of flowers and increases available propagules on stock plants. Plant growth regulators that affect branching are frequently called “chemical pinchers” because they generally inhibit the growth of the terminal shoots or enhance the growth of lateral buds, thereby increasing the development of lateral branches (Carey, 2008). They can be used to replace mechanical pinching in many crops. MATERIALS AND METHODS Crops selected included: Gaillardia aristata ‘Gallo Yellow,’ Echinacea ‘Sombrero Hot Pink,’ and Phlox paniculata ‘Laura.’ Plugs (size 72) were planted in trade gallon (3.4 liter) pots filled with a peatlite media and maintained under constant liquid feed at 200 ppm N using Peters 20-10-20. The Phlox and Echinacea were grown outside on the pad area. The outdoor plants were topdressed with Osmocote 15-9-12, 3-4 month feed at 5 g per pot. The Gaillardia was grown in a cold frame that was covered with white overwintering plastic with the sides removed for ventilation. Each plant species was set up as an individual experiment with plants arranged in a completely randomized design with six single plant replications. Destructive harvests were performed on Gaillardia and Echinacea at 6 and 8 weeks after treatment (WAT). Augeo (dikegulac sodium; OHP, Inc.) was applied as a foliar spray at 0, 400, 800, 1600 or 3200 mg/L at a volume of 210 ml/m or as a drench at 0, 40, 80, or 160 mg/L at 300 ml per pot. Configure (6-BA, Fine Americas, Inc.) was applied at 600 mg/L foliar spray at a volume of 210 ml/m as a branching comparison. Applications were made in the early morning (July 8, 2009; 7:15 am EDT, 19C, 56% RH, under sunny skies). 1 Virginia Tech, Department of Horticulture, 301 Saunders Hall, Blacksburg, VA 24061-0327 U.S.A.