Weed-infested environments lead to the improper establishment of ornamental crops, particularly in containerized production, where weeds compete more for light, water, nutrients, and space with ornamental plants due to confined conditions. Hence, the objectives of this research project were to evaluate strategic fertilizer placement methods to assess the optimum container size for containerized ornamental production to mitigate weed proliferation while promoting ornamental plant growth. Two ornamental species, Rosa rubiginosa L. (rose) and Spiraea japonica L. f. (spirea), were studied for fertilizer placement studies, while two others, Hydrangea macrophylla (Thunb.) Ser. (hydrangea) and Syringa vulgaris L. (syringa), were evaluated for container size study. These experiments were conducted in a greenhouse setting at the Horticulture Teaching and Research Centre, Michigan State University, using two commonly found weeds in nurseries, Digitaria Sanguinalis (L.) Scop. (large crabgrass) and Amaranthus hybridus L. (smooth pigweed), at densities of 0, 1, 3, and 6 for both experiments. Both studies followed a randomized complete block design with the experiments repeated twice for each study. Results showed that sub-dressing can be an efficient fertilizer placement method that controls weeds and enhances ornamental growth. Three gallon containers appeared to promote ornamental growth, particularly in hydrangeas compared to other container sizes such as 1.5-gallon and 0.67-gallon but failed to eradicate weed proliferation. However, 0.67-gallon containers reduced the growth of both weed species compared to 1.5-gallon and 3-gallon containers, though they did not promote ornamental growth and, in turn, decreased ornamental growth. Therefore, future studies on container sizes should be conducted with different ornamental and weed species possessing different growth habits to determine the optimal container size.
Read
