Factors affecting the success of the rooting process in some Proteaceae

In Europrotea and Flora United Farms, located in the Southwest Portuguese coast, the plantations were made mainly using rooted cuttings produced in their own nurseries. Since 1999, 35 ha (3600-5000 plants/ha) were planted with Protea spp., Leucospermum spp. and Leucadendron spp. rooted cuttings. This study reports the rooting data from January 1999 to September 2000 (Europrotea) and from September 2007 to December 2009 (Flora United Farms). The cuttings were selected from healthy plants from the farm fields or from stems/cuttings bought for this purpose. The basal part of each cutting was treated with a 4000 ppm IBA ethanol solution and dipped in a powder fungicide mixture. The cuttings were placed in crystal plastic bags filled up with a mixture of peat, formalin-treated sand, triturated extruded polystyrene, and placed in a greenhouse, with basal heat and mist. Dead cuttings were periodically discharged. After 1.5-2 months cuttings were regularly checked, looking for the roots which can be observed through the bags. Rooting rates varied between 10% (Protea eximia ‘Fiery Duchess’) and 100% (Leucospermum ‘Gold Dust’, Leucadendron ‘Inca Gold’). In general, Protea cuttings rooted slowly and hardly than Leucospermum and Leucadendron. However, for Protea cynaroides we can obtain rooting rates about 100% with cuttings picked five to six months after the plants overcame a frost. Decreases in the rooting rates tend to be noticed when cuttings faced long voyages before being planted. Exceptions to this behaviour were observed in Leucadendron ‘Noel Rose’ and Leucadendron ‘Blush’, being the higher rates found when cuttings travelled from commercial fields and in a few cases from nurseries in the Southern Hemisphere. A period of three to four days between picking the cuttings and placing them in the nursery, in transportation under dark and low temperatures conditions, increased the rooting rate in Leucadendron ‘Fireglow’. Season (e.g., some Leucadendron cvs.) and phenological stage (e.g., Protea ‘Brenda’) also influenced the rooting rates obtained.