Cutting Type and Time-of-Year Affect Rooting Ability of Hardy Minnesota Prunus

All species and cultivars within the genus Prunus are difficult to root. Thus, most cultivated accessions are grafted for propagule increase. The University of Minnesota Prunus germplasm and cultivar releases include a variety of ornamental and edible types that have received little research focus. Many accessions have never been evaluated for their ability to root, even though at least one sour cherry, P. cerasus ‘Northstar’, is not grafted and sold on its own rootstock. Two experiments were conducted to evaluate if cutting position, time of year, or auxin treatment were important for terminal and basal softwood-semi-hardwood rooting success of: I) P. x cistena (control); P. armeniaca ‘Westcot’, ‘Hardygold’; P. cerasus ‘Northstar’, ‘Meteor’; P. domestica ‘Superior’, P. spp. ‘Alderman’ treated with 1000 or 4000 ppm K-IBA for 10 seconds and II) P. x cistena (control) and P. spp. ‘Alderman’ treated with 80 ppm each of K-IBA and ICapA (Indole-3-caprioc acid) for 20 hr basal soak. Cuttings were taken biweekly (June 5 to September 11, 2012) and then monthly until December 4, 2012. Cuttings were scored for callus formation, root development, and bud break (leaves, flowering). The highest frequency of rooting occurred in June and again in October–December for P. x cistena and July, September–october for P. armeniaca ‘Westcot’. All other cultivars had very low rooting. Yield potential of transplantable seedlings ranged from 1.14% (P. spp. ‘Alderman’) to 24.09% (P. armeniaca ‘Westcot’) and 40.23% (P. x cistena).