DEVELOPMENT AND APPLICATION OF FOLIAR APPLIED ROOTING SOLUTIONS^©

To propagate plants from cuttings, Kees Eigenraam told me about the ‘foliar’ (leaf) application of rooting solutions with Rhizopon products. That was in 1989 when I came to know Kees. Our introduction was associated with my company, Hortus USA, importing his Dutch Rhizopon plant rooting products into the USA.
In those pre-Goggle Scholar days, I did extensive book and journal reading about plant propagation. Nowhere could I find a reference to ‘foliar’ use. Before growers used foliar methods for applying rooting hormones, plant propagation from cuttings was limited to basal methods. While he had written information, few growers outside Kees’ Dutch and European customers knew of foliar methods.
Foliar application of rooting solutions has a recent history. The earliest extensive study was Davies’ histological and physiological research comparing root formation in juvenile and mature cuttings (1978, 1980, 1982). Davies and Joiner (1980) found foliar application of water base IBA rooting solutions to be effective to induce roots. Kees developed the first commercial foliar methods in 1985. At the time, Kees did not know the research by Davies. The first commercial users were Dutch growers propagating chrysanthemum cuttings.