2017 ASHS Annual Conference

Southern highbush blueberry (Vaccinium corymbosum interspecific hybrid) has very specific soil requirements which include low soil pH and high soil organic matter. Pine bark is commonly used in the southeast United States to make low-organic matter soils suitable for commercial blueberry production and is a major cost of planting establishment and maintenance. Vaccinium arboreum is known to tolerate a broader range of soil pH and lower soil organic matter content than southern highbush blueberry. This study was conducted to evaluate Vaccinium arboreum as a rootstock for southern highbush blueberry in pine bark amended and non-amended soils. Results for the first three years following planting have been reported previously. This report provides information from the mature plantings during years 4 and 5. ‘Meadowlark’ and ‘Farthing’ southern highbush blueberry were grown in pine bark amended and non-amended soils as own-rooted plants, or plants grafted on Vaccinium arboreum. Plantings were established in 2011 at the University of Florida Plant Research and Education Unit in Citra, and at Straughn Blueberry Farm in Archer, both located in north-central Florida. In 2015 and 2016, canopy volume of grafted ‘Farthing’ on non-amended soil was not different from canopy volume of own-rooted ‘Farthing’ on pine bark amended soil. Similar results were found for ‘Meadowlark’ canopy volume. However, canopy volume of ‘Meadowlark’ tended to be larger for grafted than for own-rooted plants when grown in non-amended soil. Total berry yield of ‘Farthing’ was similar for grafted plants grown in non-amended soil compared with own-rooted plants grown in amended soil. Total yield of grafted ‘Meadowlark’ in non-amended soil was similar to (2015, Citra) or greater than (2016, Citra) own-rooted plants grown in amended soil. Mean berry weight of ‘Meadowlark’ tended to be greater for grafted plants than for own-rooted plants. Grafted ‘Meadowlark’ plants were less affected by blueberry leaf scorch than were own-rooted plants during the first 5 years after planting. Use of V. arboreum as a rootstock for southern highbush blueberry may allow for broader soil adaptation and reduced inputs such as pine bark or other sources of organic matter. However, additional research is needed to determine long-term effects on yield, fruit quality, and plant health and field survival, as well as possible cultivar effects.