Effects of indole-3-butyric acid and age of stem cuttings on root morphology, growth, and survival of Cornus sericea

Red osier dogwood (Cornus sericea L.), widely distributed throughout North America, is essential for wildlife, thus biodiversity. It is recommended for reclamation or revegetation of sites disturbed by oil and gas extraction because it tolerates a wide range of soil types and high pH levels. Since germination of this species is extremely difficult with long stratification requirements and poor germination, cuttings facilitate propagation. In this study, to develop techniques to propagate the species from stem cuttings, four concentrations of indole-3-butyric acid (IBA) and two cutting ages previous year's growth (PYG) and current year's growth (CYG) were investigated for survival and growth. After 4 months, survival rate, height growth, and shoot biomass from PYG cuttings were enhanced with IBA. In contrast, IBA did not affect these parameters in CYG cuttings. Root morphology was significantly affected by IBA concentration and cutting age. IBA, at higher concentrations, increased root surface and length. Total root surface area and length of PYG cuttings were increased, which may facilitate the absorption of essential resources and consequently increase growth. The results indicate that increasing the concentration of IBA may be an effective way to have better plant survival and growth of previous year's cuttings in red osier dogwood.