The objective of this research was to obtain a better understanding of the root growth dynamics of two southern highbush blueberry (SHB) cultivars, '8-–42′ 42′ and '9–02′, in the Western Cape, South Africa, southern hemisphere (SH). The number and length of new roots were measured from June 2020 to June 2021 in commercial orchards in the Hex River production area. Root production was similar between the cultivars and initially peaked at the onset of early winter, to coincide with flowering. A second peak occurred in mid-summer, approximately one month after fruit harvest and summer pruning (late November, SH) and continued until shoot growth declined in late autumn (early May, SH). Soil temperatures ranged between 11 and 20 °C during the first peak in root production and 17 and 31°C during the second peak, suggesting that new root production was controlled by the stage of plant development rather than soil temperature. This paper provides the first report on root development in SHB under the SH conditions and contributes towards implementing precision irrigation and fertigation strategies for evergreen systems.