Rooting and Subsequent Overwinter Survival of Stem Cuttings of Stewartia ovata

Abstract

Abstract Three experiments were conducted using stem cuttings of Stewartia ovata (Cav.) Weatherby to evaluate: 1) effects of indolebutyric acid (IBA) concentration on percent rooting and rooting index (root system size), 2) influence of N rate and medium amendments (dolomitic lime and/or complete fertilizer) on budbreak prior to overwintering and survival and shoot growth of cuttings following overwintering, and 3) effects of chilling duration on overwinter survival and subsequent shoot growth. Softwood cuttings of S. ovata were taken on June 19 and July 23, 1992, and treated with 0, 1000, 2000, 4000, or 8000 ppm IBA in 50% isopropyl alcohol. Rooting percentages and rooting index were highest for cuttings taken in June and treated with 2000 or 4000 ppm IBA. In the second experiment, cuttings were rooted in pine bark containing three different amendment combinations, and fertilized weekly with either 0, 50, 100, or 200 ppm N following root initiation. Overwinter survival was higher for cuttings rooted in pine bark or pine bark amended with lime, but decreased for cuttings in pine bark amended with lime and a complete fertilizer. Increasing N fertilization up to 200 ppm weekly stimulated budbreak prior to overwintering, resulted in greater shoot growth following overwintering, but had no effect on overwintering survival. In the third experiment, rooted cuttings were subjected to 0, 2, 4, 6, 8, or 10 weeks chilling at 6C (43F). Cuttings chilled for 10 weeks had the highest percent budbreak (survival) and greater overall shoot growth over a 12 week forcing period.