Vegetative propagation of Ceanothus velutinus using stem cuttings

Abstract

Ceanothus velutinus Douglas ex Hook. (Rhamnaceae; snowbrush ceanothus) is a native evergreen species that may be used in water-efficient landscaping. Few studies, however, have been conducted to clonally propagate this landscape-worthy species. Accordingly, experiments were designed to develop an effective propagation protocol by cuttings. Terminal cuttings of C. velutinus were collected from May to September 2019 from the Tony Grove Lake area of northern Utah. Cuttings were dipped in 1000/500 or 3000/1500 mg/l (1000/500 or 3000/1500 ppm) indole-3-butyric acid (IBA)/1-naphthaleneacetic acid (NAA) as Dip’N Grow or in the talc-based rooting hormone Hormodin 1 (1000 mg/l IBA) (1000 ppm IBA) or Hormodin 2 (3000 mg/l IBA) (3000 ppm IBA) and stuck in a rooting medium consisting of perlite and peat moss (4:1, v:v). Rooting percentage of cuttings collected in July and treated with Hormodin 2 was 22%, which was higher than for cuttings collected in other months or treated with other hormones. Cuttings were collected from the same area from June to August 2020, and similar results were observed. In August 2019, we collected terminal and subterminal cuttings; terminal cuttings performed well when compared to subterminal cuttings. In another experiment, rooting hormones were tested using cuttings collected from greenhouse-grown seedlings that were initially grown from seeds. Based on hierarchical cluster analysis, Hormodin 2 outperformed other hormones. This protocol provides a basis for the propagation of C. velutinus by cuttings. Further research could provide important improvements.