Rhizomes of wild lowbush blueberry (Vaccinium angustifolium Aiton) extend horizontally, creating spatial dependency when fertilization trials are performed. Knowing this spatial dependency would help researchers to better design field studies. Here, we used labelled nitrogen (N) fertilizer (¹⁵N-(NH₄)₂SO₄) to measure N translocation among blueberry stems for one old (56year) and one younger (15year) commercial field. Leaf ¹⁵N concentrations at the tip-dieback stage were used to monitor N acquisition. No difference between sites suggests no field age effect on N translocation. Spatial dependency and independency were reached for distances of ≤0.75 and ≥1.75m from the fertilizer application point, respectively.