The chemical defoliation of ornamental nursery shrubs Forsythia X intermedia Zab., Rosa cv. Lampion, Spiraea x bumalda Burv. cv. Froebelii, Spiraea X vanhouttei Zab.

The defoliants used on shrubs in the nursery were: ethephon, KJ, Mg(ClO₃)₂•6H₂O, CuSO₄•5H₂O, (NH₄)₂SO₄ in various concentrations separately or as mixtures. Spraying was performed on September 26-28 1972 and 1973. The most effective defoliant for <i>Rosa</i> cv. Lampion, <i>Spiraea X bumalda</i> cv. <i>Froebelii, Spiraea X vanhouttei</i> shrubs was KJ applied at a concentration of 0.2% or used in mixture with ethephon or (NH₄)₂SO₄ in lesser concentrations. Effective defoliation of many shrubs including Forsythia X intermedia was obtained with Mg(ClO₃)₂ used at a concentration of 0.24-0.48% or CuSO₄ at concentration of 2%. But at the same time these defoliants brought about comparatively the greatest retardation in shrubs development and growth and, in the case of <i>Forsythia X intermedia</i>, reducted also frost resistance.