Submist is Effective for Propagation of Korean Lilac and Inkberry by Stem Cuttings

Although overhead mist revolutionized the propagation industry, it does suffer from potential drawbacks that include the application of large volumes of water, potentially unsanitary conditions, irregular misting coverage, and leaching of foliar nutrients. We explored the feasibility of submist as an alternative as it might avoid these problems by applying water exclusively from below the cutting, which is inserted basally into an enclosed rooting chamber. We propagated cuttings of korean lilac (Syringa pubescens ssp. patula) and inkberry (Ilex glabra) using both overhead mist and submist to compare effectiveness of the systems. Cuttings of korean lilac were wounded and dipped basally into 8000 mg.L-1 of the potassium salt of indole-3-butyric acid (K-IBA), and those in the overhead mist systems were inserted into coarse perlite. Cuttings of inkberry were wounded and treated with 5000 mg.L-1 K-IBA, and those in the overhead mist systems were inserted into 50: 50 peat: perlite (by vol). Cuttings of korean lilac in the submist systems produced more than twice as many roots as cuttings in the overhead mist systems, with roots more than 2.6 times the length. Similarly, cuttings of inkberry in the submist systems produced more than three times the root counts and root lengths as cuttings in the overhead mist systems. For korean lilac, root dry weights averaged 58 mg for cuttings in the submist system, compared with only 18 mg among cuttings receiving overhead mist. Likewise, root dry weights averaged 70 and 7 mg for cuttings of inkberry propagated by submist and overhead mist, respectively. Rooted cuttings of korean lilac transplanted well into a soilless substrate, where they more than tripled their root biomass to 218 mg (vs. 59 mg for cuttings transplanted from overhead mist). We did not evaluate transplant performance of inkberry. Our results show that submist systems might merit consideration for the propagation of woody plants by leafy stem cuttings.