Light-scattering shade net increases branching and flowering in ornamental pot plants

Abstract

SummaryShaping and flowering of ornamental pot plants often involves the use of chemical growth regulators and/or intensive manual cutting in order to obtain compact plants. In this report, we examine the effect of shading ornamental pot plants with a pearl-coloured polyethylene net that increased the percentage of scattered light more than five-fold compared to a neutral black shade net, without changing the light spectrum. The two plants chosen for this study were Myrtus communis and Crowea ‘Poorinda Extasy’. The increase in scattered light due to shading with the pearl net had a dramatic effect on both plants: M. communis plants grew in a more compact form, with a larger number of branches; while, in Crowea ‘Poorinda Extasy’ plants, there was a significant increase in the number of flowers per plant. Crowea ‘Poorinda Extasy’ plants flowered throughout the year and did not seem to be dependent on a specific temperature or day-length. However, the number of flowers per plant was highest under elevated temperatures (26º/18ºC; day/night, respectively) and under a short-day regime of 10 h. This report proposes an alternative, environmentally friendly and non-labour intensive method for shaping ornamental pot plants by manipulation of the light reaching the plants.