Spiderwort (Tradescantia virginiana) is a flowering herbaceous perennial. Little information is available about its production requirements. This project’s purpose was to determine fertilizer and PGR rates for high quality growth of Spiderwort in a greenhouse production setting. The first experiment screened three plant growth regulators (PGRs) at ascending rates on three T. virginiana cultivars. The most effective rates for height suppression were paclobutrazol at 120 mgּL-1, uniconazole at 45 mgּL-1, and flurprimidol at 45 mgּL-1.

The second experiment was divided into two parts. The first screened three T. virginiana cultivars for their growth response to several nitrogen (N) rates. The second experiment used results from the first experiment and examined two cultivars response to a basic fertilizer. For experiment 1, N rates between 100 and 200 mg‧L-1 resulted in quality plant growth. The second experiment showed little difference between height, width and flowering of both cultivars with these N rates. Plant quality was similar for plants fertilized with 100 and 200 mgּL-1 N at the end of both experiments.

The third study examined how fertilization rate affects the persistence of PGR growth control. PGR rates identified as effective in experiment 1 were used. Plants fertilized with 200 mgּL-1 N were taller than those fertilized with 100 mgּL-1 N, regardless of PGR treatment. PGRs did not suppress plant growth; plant quality was similar regardless of treatment. The results of these studies indicate that PGR effectiveness in suppressing plant height may be dependent upon season, with PGR application necessary only during the spring growing season.