Comparison of Perlite and Peat:perlite Rooting Media for Rooting Softwood Stem Cuttings in a Subirrigation System with Minimal Mist

Abstract

Abstract Perlite and mixtures of milled sphagnum peat and perlite (1:16, 1:8, and 1:4 by vol) were compared as rooting media in a propagation system utilizing subirrigation with minimal mist for rooting softwood stem cuttings of nine woody plant species. The influence of rooting medium on percentage rooting, number of roots per rooted cutting, and length of the longest roots on each cutting varied with species. Composition of the media had no effect on percentage of cuttings that rooted, number of roots per rooted cutting, or length of the longest root of ‘Late Blue’ highbush blueberry (Vaccinium corymbosum L. ‘Late Blue’). Cuttings of Amur maple (Acer ginnala Maxim.) and ‘Ruby Spice’ sweet pepper bush (Clethra alnifolia L. ‘Ruby Spice’) produced the longest root in 1:4 peat:perlite, and cuttings of ‘Ruby Spice’ sweet pepper bush produced the greatest number of roots in 1:8 peat: perlite. Cuttings of redvein enkianthus [Enkianthus campanulatus (Miq.) Nichols] produced more roots in 1:8 peat:perlite than in perlite, and longer roots in 1:16 and 1:8 peat: perlite than in perlite. The number of roots per cutting of ginkgo (Ginkgo biloba L.) was greatest in 1:16 peat: perlite. Cuttings of Carolina silverbell (Halesia carolina L.) rooted in the greatest percentage in perlite, and cuttings of panicle hydrangea (Hydrangea paniculata Sieb.) rooted in the greatest percentages in perlite and 1:8 peat: perlite. The number of roots per cutting of ‘Kwanzan’ cherry and ‘Shasta’ doublefile viburnum [Viburnum plicatum Thunb.var. tomentosum (Thunb.) Rehd. ‘Shasta’] was greatest in 1:16 and 1:8 peat: perlite. Root length per cutting of ‘Kwanzan’ cherry (Prunus serrulata Lindl. ‘Kwanzan’) increased with an increase in the amount of peat in the medium. Rooting medium pH decreased and moisture content increased as the amount of peat in the media increased from 1:16 to 1:8 to 1:4 (peat:perlite, by vol).