The effect of Pinus radiata bark toxicity on the early growth of plants in containers

Fresh Pinus radiata bark will impair the growth of seedlings and struck cuttings of some species, e.g., Impatiens linearifolia, Coleus blumei cultivar ‘Golden Gem’, Engenia cyanocarpa, Hymenosporum flavum and Chrysanthemum morifolium ‘White Sands’; but not of Monstera pertusa, Camellia sasanqua ‘Lucinda’, Rhodondendron ‘Sir Robert Peel’ or Pilea cadierei. Partial elimination of the phytotoxicity was as effective as complete elimination in allowing normal growth of the plants.For sensitive species, the presence of the propagating mixture around the root systems at the time of planting helped to nullify the effects of the toxins. Bare-rooting the plants exposes them to a maximum set-back. The percentage of bark in a mixture also influenced the extent of the phytotoxicity.