Container and Field Evaluation of Three Native Shrubs Grown in Compost-Based Media

Three shrubs native to Florida, pineland privet [Forestiera segregata var. pinetorum (Small) M.C. Johnst.], Simpson's stopper [Myrcianthes fragrans (Sw.) McVaugh], and Walter's viburnum (Viburnum obovatum Walter), were container grown in a peat- or compost-based medium for 18 weeks. The formulated compost-based medium had lower initial moisture, pH, total porosity, and container capacity; and higher bulk and particle density than the other media. The compost-based medium and unamended compost both had higher levels of N, P, K, Zn, Cu, Mn, and Fe than the peat-based medium. Regardless of species, incorporation of compost in the medium did not affect plant height or shoot dry weight. Although growth indices of Walter's viburnum and pineland privet were similar among media, compost-grown Simpson's stopper had 24% greater growth index than plants grown in peat-based media. Root dry weights of Walter's viburnum grown in peat or compost-based media were 30 to 50% greater than that of plants grown in unamended compost. Regardless of species, when grown out in the landscape for an additional 32 weeks, initial container medium did not affect subsequent plant height, growth index, stem caliper, or visual quality.