A 2-year study evaluated the effects of three weed species: eclipta [Eclipta alba (L.) Hasskarl], prostrate spurge (Euphorbia supina Raf.), and wood sorrel (Oxalis stricta L.) on growth of container-grown `Gumpo White Sport' azalea (Rhododendron eriocarpum), R. x `Fashion', and Berberis thunbergii DC. var. atropurpurea `Crimson Pigmy'. Competitiveness among weed species as ranked from greatest to least was eclipta, prostrate spurge, and wood sorrel. Greater populations of eclipta and prostrate spurge resulted in decreased shoot dry weight of `Fashion' and `Gumpo White Sport' azalea. Prostrate spurge had a similar effect on `Crimson Pigmy' barberry in both small (3.8-liter) and large (15.2-liter) containers, while eclipta reduced shoot dry weight of barberry only in large containers. Wood sorrel had little effect on shoot dry weight of `Fashion' and `Gumpo White Sport' azalea.
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