Response of ‘Prize’ Azalea to Sumagic Applied at Several Stages of Shoot Apex Development

Abstract ‘Prize’ forcing azalea was treated with 15 or 30 ppm Sumagic at one of 4 stages of shoot apex development (stage 0 = vegetative; 1 = apex broadened; 2−3 = sepals and petals initiated; 4 = stamen initiated) in 2 experiments. Plants were taller and broader as the application was delayed; these parameters decreased with increasing Sumagic rate. Bypass shoot count decreased quadratically with increasing rate, and was not affected by stage of development (SOD) in one experiment but decreased when plants were treated at a later SOD in a second experiment. Time to flower increased and flower count decreased when plants were treated at a later SOD. Plants treated at SOD 0 flowered earlier with more blooms or at a similar time with a similar flower count to control plants.