Propagation of Herbaceous and Woody Perennials in Submist and Overhead Mist Systems

Submist aeroponic propagation systems apply mist to the bases of cuttings, rather than from overhead. These systems improve rooting in some plant species and reduce water usage compared to overhead mist systems. Submist systems, which were supplemented with infrequent overhead mist, were used to propagate stem cuttings collected from six plant species: bluestar (Amsonia tabernaemontana Walter), purple smoke false indigo (Baptisia australis x B. alba ‘Purple Smoke'), threadleaf coreopsis (Coreopsis verticillata L.), panicle hydrangea (Hydrangea paniculata Siebold), sweetgale (Myrica gale L.), and ninebark (Physocarpus opulifolius (L.) Maxim ‘Diablo'). The submist systems were compared to traditional overhead mist with a solid propagation medium. Rooting was better in overhead mist for cuttings of threadleaf coreopsis and purple smoke false indigo. Rooting was comparable between systems for all other species (bluestar, panicle hydrangea, sweetgale, and ninebark). In the submist systems, water usage was reduced by 67% compared to overhead. This is probably due to reduced evaporative water loss and more targeted application of water directly to cuttings, resulting in less water lost on the ground or benchtops. Species used in this study: Amsonia tabernaemontana Walter, Baptisia australis x B. alba ‘Purple Smoke', Coreopsis verticillata L., Hydrangea paniculata Siebold, Myrica gale L., Physocarpus opulifolius (L.) Maxim ‘Diablo'. Chemicals used in this study: KIBA (potassium salt of indole-3-butyric acid).