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Reclaimed water provides a reliable and economical alternative source of irrigation water for landscape use but may have elevated levels of salts that are detrimental to sensitive landscape plants. Landscape professionals must use salttolerant plants in regions where reclaimed water is used. Ornamental grasses are commonly used as landscape plants in the Intermountain West of the United States due to low maintenance input, drought tolerance, and unique texture. Six ornamental grass species, including Acorus gramineus (Japanese rush), Andropogon ternarius (silver bluestem), Calamagrostis x acutiflora (feather reed grass), Carex morrowii (Japanese sedge), Festuca glauca (blue fescue), and Sporobolus heterolepis (prairie dropseed), were evaluated for salinity tolerance. Plants were irrigated every 4 days with a fertilizer solution at an electrical conductivity (EC) of 1.2 dS·m–1 (control) or with a saline solution at an EC of 5.0 dS·m–1 (EC 5) or 10.0 dS·m–1 (EC 10). At 47 days, most species in EC 5 exhibited good visual quality with averaged visual scores greater than 4.6 (0 = dead, 5 = excellent). In EC 10, most A. gramineus plants died, but C. x acutiflora, F. glauca, and S. heterolepis had no foliar salt damage. At 95 days, C. x acutiflora, F. glauca, and S. heterolepis in EC 5 had good visual quality with averaged visual scores greater than 4.5. Acorus gramineus, A. ternarius, and C. morrowii showed foliar salt damage with averaged visual scores of 2.7, 3.2, and 3.4, respectively. In EC 10, A. gramineus died, and other grass species exhibited moderate to severe foliar salt damage, except C. x acutiflora, which retained good visual quality. Plant height, leaf area, number of tillers, shoot dry weight, and/or gas exchange parameters also decreased depending on plant species, salinity level, and the duration of exposure to salinity stress. In conclusion, A. gramineus was the most salt-sensitive species, whereas C. x acutiflora was the most salt-tolerant species. Festuca glauca and S. heterolepis were more tolerant to salinity than A. ternarius and C. morrowii. Calamagrostis x acutiflora, F. glauca, and S. heterolepis appear to be more suitable for landscapes in which reclaimed water is used for irrigation. Plant responses to saline water irrigation in this research could also be applied to landscapes in salt-prone areas and coastal regions with saltwater intrusion into aquifers and landscapes affected by maritime salt spray. [ABSTRACT FROM AUTHOR]

Viburnums are widely used in gardens and landscapes throughout the United States. Although salinity tolerance varies among plant species, research-based information is limited on the relative salt tolerance of viburnum species. The morphological and growth responses of 12 viburnum taxa to saline solution irrigation were evaluated under greenhouse conditions. Viburnum taxa included Viburnum 3burkwoodii, V. cassinoides 'SMNVCDD', V. dentatum 'Christom', V. dentatum var. deamii 'SMVDLS', V. dilatatum 'Henneke', V. 3'NCVX1', V. nudum 'Bulk', V. opulus 'Roseum', V. plicatum var. tomentosum 'Summer Snowflake', V. pragense 'Decker', V. 3rhytidophylloides 'Redell', and V. trilobum. A nutrient solution at an electrical conductivity (EC) of 1.3 dS·m-1 (control) or saline solutions at ECs of 5.0 and 10.0 dS·m-1 were applied eight times over a 9-week period. Growth, visual quality, and morphological characteristics were quantified at the 4th week and 8th-9th week to assess the impact of salinity stress on the viburnum taxa. Saline solution irrigation imposed detrimental salinity stress on viburnum plant growth and visual quality, and the degree of salt damage was dependent on the salinity levels of irrigation solution and the length of exposure to salinity stress as well as viburnum taxa. Viburnum 3burkwoodii and V. 3'NCVX1' had little foliar salt damage during the entire experiment, except those irrigated with saline solution at an EC of 10.0 dS·m-1 exhibited slight to moderate foliar salt damage at the eighth week. Viburnum dilatatum 'Henneke', V. plicatum var. tomentosum 'Summer Snowflake', and V. trilobum irrigated with saline solution at an EC of 5.0 dS·m-1 had slight and severe foliar salt damage at the 4th and 8th week, respectively. Plants irrigated with saline solution at an EC of 10.0 dS·m-1 exhibited severe foliar salt damage at the 4th week, and all died by the 8th week. Other viburnum taxa also showed various foliar salt damage, especially at an EC of 10.0 dS·m-1. The shoot dry weights of V. 3burkwoodii and V. 3'NCVX1' irrigated with saline solution at ECs of 5.0 and 10.0 dS·m-1 were similar to those in the control at both harvest dates. However, the shoot dry weight of other tested viburnum taxa decreased to some extent at the 9th week. A cluster analysis concluded that V. 3burkwoodii and V. 3'NCVX1' were considered the most salttolerant viburnum taxa, whereas V. dilatatum 'Henneke', V. plicatum var. tomentosum 'Summer Snowflake', and V. trilobum were sensitive to salinity levels used in this study. This research may guide the green industry to choose relatively tolerant viburnum taxa for landscape use and nursery production where low-quality water is used for irrigation. [ABSTRACT FROM AUTHOR]

Prairie junegrass [Koeleria macrantha (Ledeb.) Shultes] is a perennial, shortgrass prairie species distributed throughout the Northern Hemisphere that is being evaluated for use as a low-input turf. In June 2007, 300 genotypes representing collection locations derived from Colorado, Nebraska, and Minnesota germplasm were grown and evaluated 3 years for turfgrass performance characteristics in a randomized complete block design with five clonal replications at two locations (St. Paul, MN, and Becker, MN). After establishment, plots received no supplemental irrigation or fertility and were mowed weekly to a height of 6.4 cm. Broad-sense heritability estimates were calculated on a clonal mean (Hc) and single-plant (Hsp) basis for turf quality (Hc = 0.62, Hsp = 0.13), crown density (Hc = 0.55, Hsp = 0.09), mowing quality (Hc = 0.59, Hsp = 0.09), and genetic color (Hc = 0.45, Hsp = 0.06). The heritability estimates indicate that selection for these traits should result in significant gains in germplasm improvement. Differences were observed in the means and variances among clones, collection locations, and/or collection regions for many of the traits evaluated including rust severity (Puccinia spp.), spring green-up, plant height, lateral spread, vertical regrowth, and flowering traits. The positive correlations among some of these traits and those with moderate heritability estimates should allow for multi-trait selection in cultivar development. [ABSTRACT FROM AUTHOR]

The authors investigated salinity tolerance of four intermountain western United States native (Penstemon palmeri, Mirabilis multiflora, Geranium viscosissimum, and Eriogonum jamesii) and four common (Echinacea purpurea, Lavandula angustifolia, Leucanthemum xsuperbum 'Alaska', and xPenstemon mexicali 'Red Rocks') ornamental herbaceous perennials. Each was irrigated with a solution containing 2 CaCl2: 1 NaCl(M ratio) at salinity levels of 0 (control), 1000, 3000, and 5000 mg⋅L-1 during two 8-week experiments. They measured weekly visual quality and gas exchange and final shoot and root dry weights. Mirabilis multiflora, L. xsuperbum, and L. angustifolia maintained high visual quality and 100% survival across salinity levels. However, dry weights for L. xsuperbum decreased at salt levels ≥ 3000 mg⋅L-1 in both experiments and for L. angustifolia in one experiment. Mortality rates of 12% to 100% were observed for the remaining five species irrigated with 3000 and 5000-mg⋅L-1 solutions. Visual quality of P. pahneri, G. viscosissimum, and E. purpurea varied with time of year the experiment was conducted, with low visual quality associated with high temperatures and light intensities, whereas dry matter and gas exchange responses to salinity were similar between the two experiments. Penstemon xmexicali and E. jamesii exhibited high mortality, low visual quality, and low gas exchange in the case of E. jamesii at high salinity treatments regardless of when experiments were conducted. Based on visual quality responses, M. multiflora, L. xsuperbum, and L. angustifolia are relatively more salt tolerant, and P. xmexicali and E. jamesii are relatively more intolerant, than the three other species. Penstemon palmeri, G. viscosissimum, and E. purpurea exhibited intermediate tolerance to salinity with acceptable quality during periods of cool temperatures and lower light intensities. [ABSTRACT FROM AUTHOR]