Rootstock Evaluation

Work is currently being done to evaluate the Sparkleberry, Vaccinium arboreum, in its potential to be used as a rootstock for grafting three different kinds of highbush blueberry, which include the varieties ‘Draper,’ ‘Liberty’ and ‘Aurora.’  For more information on our grafting experiment, please visit our page “Blueberry Tree Project.”  Here at the North Willamette Research and Extension Center we have been growing V. arboreum in both the greenhouse and in field trials, to see which are the hardiest plants that would be the ideal rootstock. 

The plants that are being grown in our greenhouse have been started from tissue cultures that were obtained from several parent plants originating in Texas.  Even from the beginning there were noticeable differences between plant structure and vigor, and over the course of this trial those differences have become even more pronounced.  The result has been than some strains have produced plants that exhibit the ideal characteristics for being a graftable rootstock, while others have developed into weak and sickly plants.  Those plants which have a fairly straight trunk, are vigorous, and have a healthy color will be selected to be used as rootstock material for our grafting experiment.   Shaping the plants has been no small feat, and has required dedication to pruning the plants regularly to produce a strong single stem, which then branches into a tree-like canopy.

The field trial contains well over 300 plants.  These plants were started from seeds that were collected from three different locations in the United States- Texas, Oklahoma and Florida.  The plants are now a few years old, and are regularly measured to observe changes in growth, sucker production, and to evaluate color and vigor.  

Author: Heather Andrews