Optimizing container production of American fly honeysuckle (Lonicera canadensis L.), beaked filbert (Corylus cornuta Marsh.), and maple leaf viburnum (Viburnum acerifolium L.)

American fly honeysuckle (Lonicera canadensis L. [Caprifoliaceae]), beaked filbert (Corylus cornuta Marsh. [Betulaceae]), and maple leaf viburnum (Viburnum acerifolium L. [Caprifoliaceae]) are native shrubs useful for northeastern and north central United States landscapes with dry shaded conditions. The objectives of this study were to evaluate the impact on growth in containers of 1) growth media amended with expanded shale at three different rates for all three species, 2) two different rates of controlled-release fertilizer for all three species, and 3) pruning of maple leaf viburnum. Expanded shale added to growth media composed of four parts pine bark, two parts peat moss and one part sand did not improve growth for these species, and significantly larger plants of American fly honeysuckle were produced in control media (lacking expanded shale) than in amended media. Over a 2-year production cycle, the higher fertility rate of 2.5 g N/pot produced American fly honeysuckle plants that were larger and had more shoots than American fly honeysuckle plants that received 1.0 g N/pot. For beaked filbert, the higher fertility rate can produce greater growth, but may not do so every year. Fertility rate did not impact growth of maple leaf viburnum. Plants of maple leaf viburnum that were pruned after transplanting to trade #1 containers had visual quality ratings two times greater than unpruned plants. Pruned maple leaf viburnum had equivalent plant height and width and a more symmetrical and full appearance than unpruned maple leaf viburnum plants.