Strangulation and IBA treatments as an effective method to propagate tree peonies, Paeonia suffruticosa

Abstract

The tree peony (Paeonia suffruticosa Andr.) is a deciduous woody perennial endemic to Central Plains, Northwest, and Southern Yangtse, China, and is loved by the general public, horticulturists and gardeners all over the world. Tree peonies cultivars are usually propagated vegetatively by grafting and division; however, these methods are inefficient for mass-propagation. Two stem wounding methods (stem girdling and strangulation) and four concentrations of 4-(1H-Indol-3-yl) butanoic acid (IBA) (0, 500, 1200, and 2000 mg/L) treatments were evaluated in ‘Luoyang Hong’, ‘High Noon’, ‘Xiang Yu’ and ‘Fugui Mantang’ to find an effective and easy method of mass-propagation. Shoots that rooted while attached to the branches were separated from the branches and transplanted to access the success rates of propagation. The cultivar had significant effects on all root rooting responses. However, stem girdling and strangulation did not affect the root formation responses. Root formation parameters (the number, length, and diameter of the primary roots), especially of ‘Xiang Yu’, were improved in response to the interaction between stem wounding and IBA treatments. The survival percentage exceeded 61% when rooted plants were transplanted, except for ‘High Noon’. It is recommended to propagate tree peonies with stem strangulation and 500–1200 mg/L IBA to increase the efficacy of mass propagation.