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Perennials grown in 5.7-cm containers received two root treatments (mechanical root-pruned and non-pruned) prior to field planting. During the 1996 season, the two root treatments and five irrigation treatments, (0%, 25%, 50%, 75%, 100%) ET0 (reference crop evapotranspiration), were tested on Delosperma cooperii, Delosperma nubigenum, Polygonum affine, and Veronica liwanensis and evaluated on the basis of plant growth and visual ratings. No significant change in height occurred in any species for both root or irrigation treatments. No significant change in width or density occurred in D. cooperii, from root treatment; however irrigation treatments below 50% resulted in a significant decrease in width. Significant deceases in width also occurred in all species from irrigation treatments. Mechanically root-pruned plants resulted in a significant decrease in density of D. nubigenum, P. affine, and V. liwanensis and a decrease in width in P. affine.
During the 1996 season, pre-emergent herbicides were applied to container-grown herbaceous perennials and evaluated on the basis of weed control, phytotoxicity, and effect on plant growth. The herbicides and rates were: Napropamide (Devrinol 10G), 0.72 and 1.44 kg a.i./ha; Oryzalin (Surflan 40AS), 0.36 and 0.72 kg a.i./ha; Oxadiazon (Ronstar 2G), 0.72 and 1.44 kg a.i./ha; Oxyfluorfen + Oryzalin (Rout 3G), 0.54 and 2.16 kg/ha; Oxyfluorfen + Pendimethalin (Scott's OH II),0.54 kg a.i./ha; and Trifluralin (Treflan 5G), 0.72 and 1.44 kg a.i./ha. Herbicides were applied to Campanula carpatica, Dianthus gratianopolitanus, Gaillardia × `Baby Cole', Penstemon × `Husker's Red', and Phlox subulata `Emerald Blue'. Phytotoxicity symptoms (visual defects and less height) were apparent with Oryzalin on Penstemon (at both rates) and on Phlox (0.72 kg a.i./ha). Weed control was significantly less with Trifluralin and Napropamide when compared to the other herbicides.