Maturation rate, pod production, and density of common milkweed (Asclepias syriacaL.) were determined at sites in east-central Missouri. Emergence of milkweeds in May was followed by blooming of flowers in late June, production of full-size follicles (average of 5.1 per plant) by late July, and release of seed in mid-September. Density was 1 to 3 plants per m2and spacing of plants in 1.4 m2samples was equidistant. Significant. positive correlations were found between mean height of milkweeds and pH, magnesium and calcium concentrations in the soil, and between density and pH of the soil.