Evaluation of Honey as a Rooting Adjuvant for Cutting Propagation of Three Common Nursery Crops

Plant propagation is a labor-intensive process in the nursery and greenhouse industry, with labor accounting for 41.4% of expenditures in 2019—$4.8 billion of the $11.6 billion total. Labor availability remains a critical issue, and current methods of applying root-promoting compounds to cuttings often yield inconsistent rooting responses. This research investigated honey as a rooting adjuvant and its effects on rooting in Red Cascade™ miniature rose (Rosa ‘MOORcap’), common camellia ( Camellia japonica ), and southern magnolia ( Magnolia grandiflora ‘Little Gem’). For Red Cascade™ rose, adding honey to water-soluble indole-3-butyric acid (IBA) solutions did not improve root counts compared to IBA alone. However, 1000 µL∙L⁻ 1 IBA produced more roots than 250 µL∙L⁻ 1 IBA. Camellia and magnolia cuttings were treated with multiflora, Manuka, or commercial honey, alongside IBA rates of 0 to 4500 µL∙L⁻ 1 . In camellia, honey type or auxin rate did not significantly affect rooting, but local and multiflora honey combined with higher IBA rates increased root counts. For magnolia, multiflora honey improved both root number and quality, outperforming other treatments. While honey showed limited benefits for camellia and rose, multiflora honey demonstrated potential economic advantages for magnolia propagation, enhancing root quality and quantity for producers.