Wetlands are complex ecosystems having considerable spatial variability. Understanding soil spatial relationships in wetlands is difficult because of the number of factors that affect soil properties. We established a nested sampling design within five small, forested and scrub‐shrub palustrine wetlands in Virginia to examine soil spatial variability within and among sites. Sampling was based on relative elevation intervals within each wetland and soil depth within each sampling unit. Soils were analyzed to determine variability in nutrient status, pH, organic C content, and particle‐size distribution (PSD). Elevation contributed the least amount to the total variability (variability among sites) for nearly every parameter. Depth from the soil surface explained the most total variability in regard to PSD, indicating that parent material stratification in these alluvial wetlands strongly influences soil physical properties. Most of the total variability in the soil chemical parameters was explained by site. Within sites, elevation trends were observed for particle‐size and chemical parameters in most of the wetlands. Elevation trends were related to water table levels and the depositional environment. Within elevation sampling units, particle‐size and chemical parameters were shown to be significantly related to depth from the soil surface (at the 0.05 level). These relationships could be attributed to the stratified nature of alluvial soils and the accumulation of organic matter at or near the soil surface. Pedon sampling locations were spaced ≈1 m apart and therefore showed less random variability than elevation sampling locations spaced throughout the 0.25‐ to 0.35‐ha study areas. Soils were classified as Endoaquepts, Humaquepts, Dystrudepts, Endoaquents, and Fluvaquents, depending on the wetland site.
Many vigorous herbaceous perennials need early growth regulation. Treatment at the plug stage could improve early growth control or maintain product size in the plug tray. Concise (uniconazole, Fine Americas, Inc.), is a growth regulator labeled for use on ornamental greenhouse crops in the US. We treated plugs of five herbaceous perennials with a 2-minute dip into 0, 1, 2, 3, 4 or 5 mg/L Concise the day before planting into 1.1-liter pots filled with a peat-lite medium (ornamental grasses were maintained in the plug pots). Plant height was determined at 2 week intervals after treatment (WAT). Concise reduced shoot growth in a linear or quadratic correlation for all crops except Gaillardia × grandiflora 'Goblin' which was not affected by the treatments. The ornamental grasses differed in responsiveness with Miscanthus sinensis 'Gracillimus' showing little response until 8 WAT while Calamagrostis × acutifolia 'Karl Foerster' exhibited a 22% reduction in plant height at 2 WAT with a 1 mg/L Concise dip followed by a 31% height reduction and 26% reduction in shoot dry weight at 12 WAT. A 1 mg/L liner dip of Concise gave significant height reduction of Phlox paniculata 'David' and Rudbeckia fulgida var. sullivantii 'Goldsturm' through 8 and 10 WAT, respectively. Liner dips are an effective means of growth regulation that can reduce worker contact with the chemical solutions and provide baseline control of vigorous or hard-to-control herbaceous perennial crops.
Many herbaceous perennials would benefit from additional branching to provide fuller pots in shorter production times. Cyclanilide (Tiberon, OHP, Inc., Mainland, PA, USA), a new product recently labeled in the USA for branching of woody ornamentals, was evaluated on several herbaceous perennials over two seasons. Cyclanilide was applied as a foliar spray to established plants grown in 1.1-L pots filled with a peat-lite medium in late summer. Plant height and number of branches were determined at two week intervals after treatment (WAT). Cyclanilide improved the lateral branching of Phlox paniculata 'Bright Eyes' with an eight-fold increase in the number of lateral branches per plant at 6 WAT with 20 mg/L (control 2.2 vs. 20 mg/L 17.8 branches). Higher rates of cyclanilide did not further increase the number of lateral shoots but did increase the phytotoxicity symptoms. Echinacea 'Ruby Star' treated with 20 mg/L cyclanilide had twice the basal branches as the untreated control. Lateral branching of Coreopsis 'Sweet Dreams' was also doubled by treatment with 20 mg/L cyclanilide. However, even 20 mg/L cyclanilide resulted in unacceptable phytotoxicity damage. Therefore, the study was repeated in the spring with lower rates (0, 5, 10, 15, 20, 25, 30 mg/L cyclanilide) applied to three cultivars of Echinacea, 'Sunrise,' 'Sundown' and 'Double Decker', Phlox paniculata 'Blue Boy' and Coreopsis 'Sweet Dreams'. Only Phlox showed a significant improvement in branching for these spring-planted and spring-treated crops. Although cyclanilide may increase branching of some perennials, phytotoxicity may limit its use for spring production, and there are obviously production issues that affect its efficacy.
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