Cutting Propagation of Juniperus osteosperma

Junipers are a diverse group of landscape plants with potential for application in drought tolerant landscapes.  The Utah juniper (Juniperus osteosperma) is of particular interest because it is highly adapted to the Intermountain region and some specimens have characteristics desirable in landscape design.  However, unlike other junipers, Utah juniper is not easily vegetatively propagated.  The effect of media, auxin concentration, and propagation environment on rooting of cuttings was examined by collecting 15 cm terminal cuttings from several wild, juvenile Utah junipers in Park Valley, UT on 16 Nov.  2010.  Cuttings were randomly assigned to treatments (n=18) of 2 perlite : 1 peat  or 4 perlite :1 peat (by volume)  rooting substrate;  0, 1000, 3000, or 8000 ppm IBA as Hormodin 1, 2, or 3; and either  an open, intermittent mist bench (7 s mist/30 min during the day) or a white polyethylene tent (mist for 30 s at 0900 and 1300 HR).  All cuttings were in the same greenhouse with 18/15.5 °C D/N temperatures, 16 hour days, and bottom heat at 21 °C.  Each cutting was defoliated up to 4 cm from the base, wounded on the bottom 15 mm, dipped in water and then in the hormone treatment to a depth of 15 mm before sticking in moist media in 606 flats (63.5 x 63.5 x 76.2 mm cells) and placing on the bench.  Misting was with deionized water and cuttings were irrigated as needed with culinary water.  Since cuttings were not placed randomly in flats, the flats were randomly assigned new positions within mist bench or tent treatments every two weeks.  On 21 Jan. 2011 all cuttings were analyzed for rooting.  Un-rooted cuttings were rinsed, re-dipped with hormone and returned to their previous conditions.  On 25 Mar. 2011 the evaluation was repeated and final data taken including rooting, number of roots per cutting, presence of callus, foliage quality, and root or stem disease.   Overall 25% of cuttings rooted, with up to 14 roots per cutting.  The highest rooting percentage (66%) was found in the poly tent, 8000 ppm IBA, and 2 perlite : 1 peat treatment.  These results indicate that while recalcitrant, selected specimens of juvenile Utah juniper can be successfully propagated by cuttings.