Two experiments, one utilizing softwood cuttings and the other semi-hardwood cuttings, were conducted to investigate the influence of growth stage and auxin treatment on rooting four related clones of eastern redbud (Cercis canadensis L.). The four clones were ‘Flame’ (C. canadensis L. ‘Flame’), dwarf white, and two selections (NC99-6-1 and NC99-6-2) of an F1 generation derived from a cross of ‘Flame’ and dwarf white. At each growth stage, rooting responses of the clones varied and were influenced greatly by auxin treatment, demonstrating the variable rooting potential of the genotypes. In both studies, ‘Flame’ rooted well [63% rooting in the softwood study when treated with the potassium (K) salt (K-salt) of indolebutyric acid (IBA) at 5000 mg·L−1 (ppm), 83% rooting when treated in the semi-hardwood study with K-IBA at 10,000 mg·L−1], indicating stem cuttings may be a commercially feasible means of propagation for ‘Flame.’ Softwood cuttings of dwarf white (46%) and NC99-6-2 (75%) rooted best when treated with K-IBA at 15,000 mg·L−1, whereas softwood cuttings of NC99-6-1 rooted best (46%) when treated with K-IBA at 10,000 mg·L−1. Dwarf white and the F1s rooted poorly in the semi-hardwood study.

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Author notes

This research was funded in part by the North Carolina Agricultural Research Service (NCARS), Raleigh, NC 27695-7643. Special thanks to Dennis J. Werner, Director, JC Raulston Arboretum, NC State University, for guidance and providing plant material. Technical assistance of William M. Reece and Layne K. Snelling is gratefully acknowledged. From a thesis submitted by J.M.W. in partial fulfillment of the requirements for the MS degree.

2Graduate Teaching Assistant.

3Alumni Distinguished Graduate Professor and corresponding author. frank_blazich@ncsu.edu

4Former Alumni Distinguished Undergraduate Professor. Currently: Professor and Head, Department of Horticulture, Forestry, and Recreation Resources, 2021 Throckmorton Plant Sciences Center, Kansas State University, Manhattan, KS 66506. slwarren@ksu.edu