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Ornamental grasses are popular in urban landscapes in Utah and the Intermountain West United States, one of the driest and fastest growing regions in the United States. This experiment evaluated the responses of five ornamental grass species [blue grama (Bouteloua gracilis), indian sea oats (Chasmanthium latifolium), ‘Blue Dune’ sand ryegrass (Leymus arenarius), pink muhly grass (Muhlenbergia capillaris), ‘Foxtrot’ fountain grass (Pennisetum alopecuroides)] and two ornamental grasslike species [fox sedge (Carex vulpinoidea), common rush (Juncus effusus)] to saline irrigation water in a greenhouse. Plants were irrigated weekly with a nutrient solution at an electrical conductivity (EC) of 1.2 dS·m^–1 (control) or saline solutions at an EC of 5.0 or 10.0 dS·m^–1. At the first harvest (9 weeks after the initiation of treatment), sand ryegrass, pink muhly grass, and fountain grass irrigated with solutions at an EC of 5.0 and 10 dS·m^–1 had good visual quality with no or minimal foliar salt damage; however, the remaining species exhibited slight or moderate foliar salt damage. There were no significant differences in shoot dry weight (DW) among treatments within any species, except fox sedge and fountain grass. At the second harvest (18 weeks after the initiation of treatment), sand ryegrass, pink muhly grass, and fountain grass still had no or minimal foliar salt damage, and indian sea oats and fox sedge exhibited slight or moderate foliar salt damage. Compared with the control, all species irrigated with solutions at an EC of 10.0 dS·m^–1 had reduced shoot DWs with the exception of blue grama. However, only common rush and pink muhly grass irrigated with solutions at an EC of 5.0 dS·m^–1 had lower shoot DWs than the control. These results demonstrated that seven ornamental grass or grasslike species had a very strong tolerance to the salinity levels used in the 4-month experiment. Although plant growth was inhibited as a result of saline irrigation, plant visual quality of sand ryegrass, pink muhly grass, and fountain grass was still acceptable. These three species appear to be more suitable for landscapes in which saline irrigation water is used. Further research is needed to evaluate more ornamental grasses for landscapes in salt-prone areas and nearby coastal regions.

‘Coy’ alder-leaf mountain mahogany (Cercocarpus montanus) is a new cultivar developed from a species native to the western United States with potential for use in xeriscaping, rock gardens, and water-efficient landscaping. However, efficient propagation methods are not well developed for it. In this study, cutting propagation of ‘Coy’ alder-leaf mountain mahogany was investigated over 3 years to evaluate the effects of wounding method, rooting hormone, type of cuttings collected, and time for cutting collection on rooting. In May, Jul, and Sep 2020, 2021, and 2022, nondormant hardwood subterminal cuttings and/or semihardwood terminal cuttings were collected for wounding studies. Before the treatment with 3000 mg·L⁻¹ indole-3-butyric acid (IBA) in powder, cuttings were wounded either by scraping one side (scrape) or by perpendicular cuts around the base (cut), and cuttings without additional wounding were used as the control. Similarly, subterminal and terminal cuttings of ‘Coy’ alder-leaf mountain mahogany were collected during the same time and were used for hormone treatments. Cuttings were treated with 1000 or 3000 mg·L⁻¹ IBA in powder or 1000/500 or 3000/1500 mg·L⁻¹ IBA/NAA (1-naphthaleneacetic acid) in solution. Wounding by cut or scrape increased the rooting percentage. In addition, most cuttings wounded by the scrape method had better rooting than those wounded with cuts. On the basis of hierarchical cluster analyses, cuttings treated with 3000 mg·L⁻¹ IBA in powder had greater rooting than those treated with other hormones. Therefore, our research showed that successful rooting of subterminal or terminal stem cuttings of ‘Coy’ alder-leaf mountain mahogany can be achieved through wounding using scrape method and by treatment with 3000 mg·L⁻¹ IBA in powder.

The goal of this experiment was to evaluate the efficiency of foliar application of dikegulac sodium on increasing the lateral branching of ‘Merritt’s Supreme’ bigleaf hydrangea (Hydrangea macrophylla). Plants were grown in greenhouses at two locations including El Paso, TX and Kosciusko, MS. Two weeks before application of dikegulac sodium, half of plants were hand-pinched leaving two nodes. Foliar spray of dikegulac sodium at 400, 800, or 1600 mg·L⁻¹ was then applied to pinched and unpinched plants. There were two additional control treatments: pinched or unpinched without application of dikegulac sodium. Data were collected at 2 weeks, 6 weeks, 80 days, and 10 months after treatments. Bigleaf hydrangea plants exhibited severe phytotoxicity including interveinal chlorosis or bleaching of new growth at 2 weeks after application of dikegulac sodium with more pronounced symptoms at higher dikegulac sodium concentrations. The severity of phytotoxicity symptoms became less significant at 6 weeks after treatment. The effect of dikegulac sodium on bigleaf hydrangea plant growth, number of branches, and number of flowers depended on both locations and dosages. In El Paso, TX, dikegulac sodium at 800 or 1600 mg·L⁻¹ inhibited bigleaf hydrangea plant growth at 6 weeks and 80 days after treatment, and this effect disappeared at 10 months after treatment. Dikegulac sodium at all tested dosages doubled or tripled the number of branches of pinched or unpinched bigleaf hydrangea, respectively, at 80 days after treatment. At 10 months after treatment, the number of branches and flowers of bigleaf hydrangea plants tended to increase, but was insignificant. In Kosciusko, MS, dikegulac sodium at 1600 mg·L⁻¹ reduced the plant growth at 6 weeks after treatment. This treatment increased the number of branches and flowers of unpinched plants by 196% and 95% and pinched plants by 53% and 31%, respectively, at 10 months after treatment. Dikegulac sodium application could be used to increase number of branches and flowers and produce compact ‘Merritt’s Supreme’ bigleaf hydrangea. However, the efficacy varied with environmental conditions.

In response to the growing demand for specialty cut flowers, floral crops are increasingly produced in semiarid areas where soil salinity can impact crop timing, reduce stem length, and decrease yield. The goal of this study was to investigate the salinity sensitivity of ‘Carmel’ and ‘Galilee’ anemone (Anemone coronaria), and ‘Amandine’ and ‘LaBelle’ ranunculus (Ranunculus asiaticus) with respect to physiological characteristics and marketable yield. Nine plants were irrigated weekly for 8 weeks with a nutrient (control) solution with an electrical conductivity (EC) of 0.5 dS⋅m^–1 or saline solutions prepared by adding sodium chloride and calcium chloride dihydrate to a nutrient solution to obtain an EC of 1.5, 2.5, 3.5, 4.5, or 5.5 dS⋅m^–1. Yield was evaluated by dividing stems into marketable and cull grades based on length and bloom quality. At the end of the study, the visual quality of the plants was scored, and gas exchange data were collected using a portable photosynthesis system. Cultivars of each species responded similarly, and marketable yields were low across all treatments, with average marketable yields (mean ± sd) of 1.7 ± 0.6 stems/plant for anemone and 1.2 ± 0.1 stems/plant for ranunculus. Visual quality (0–5 scale, with 0 = dead and 5 = excellent) decreased from 3 to 1 for anemone and 3 to 2 for ranunculus as EC increased from 0.5 to 4.5 dS⋅m^–1 and 0.5 to 5.5 dS⋅m^–1, respectively. Anemone leaf greenness decreased by 48%, stomatal conductance (g _S) decreased by 79%, transpiration (E) decreased by 75%, and net photosynthesis (P_n) decreased by 92% when irrigation solution EC increased from 0.5 to 4.5 dS⋅m^–1. The ranunculus growth index decreased by 17%, leaf greenness decreased by 45%, and E decreased by 23% as irrigation solution EC increased from 0.5 to 5.5 dS⋅m^–1. Both anemone and ranunculus can be considered sensitive to salinity, indicating the importance of careful soil management in cut flower production systems in semiarid areas that are at risk for elevated soil salinity.

Marigolds (Tagetes sp.) are ornamental plants with fine-textured, dark green foliage, and yellow, orange, or bicolored flowers. The relative salt tolerance of eight marigolds [‘Discovery Orange’, ‘Discovery Yellow’, ‘Taishan Gold’, ‘Taishan Orange’, and ‘Taishan Yellow’ african marigold (Tagetes erecta); ‘Hot Pak Gold’, ‘Hot Pak Orange’, and ‘Hot Pak Yellow’ french marigold (Tagetes patula)] was evaluated in a greenhouse experiment. Plants were irrigated weekly with nutrient solution at an electrical conductivity (EC) of 1.2 dS·m⁻¹ (control) or saline solutions at an EC of 3.0 or 6.0 dS·m⁻¹ (EC 3 or EC 6). Marigold plants began to show foliar salt damage (leaf burn and necrosis) at 6 weeks after the initiation of treatment. At harvest (9 weeks after the initiation of treatment), ‘Discovery Orange’, ‘Discovery Yellow’, ‘Taishan Gold’, and ‘Taishan Yellow’ plants exhibited severe foliar salt damage with visual scores less than 2 (on a scale of 0 to 5, with 0 = dead and 5 = excellent with no foliar salt damage) in EC 6. In the same treatment, ‘Hot Pak Gold’ and ‘Taishan Orange’ plants all died and only one of nine ‘Hot Pak Orange’ and ‘Hot Pak Yellow’ plants survived. In EC 3, all cultivars had slight or minimal foliar salt damage with visual scores ≈4 with the exception of Taishan Gold and Taishan Orange plants that showed moderate foliar damage with a visual score of 2.3 and 2.1, respectively. Treatment EC 3 reduced the flower number of ‘Discovery Orange’, ‘Discovery Yellow’, ‘Hot Pak Gold’, and ‘Hot Pak Yellow’ by 52%, 28%, 50%, and 30%, respectively, whereas EC 6 decreased the flower number of ‘Discovery Orange’ and ‘Discovery Yellow’ by 48% and 52%, respectively. In addition, both EC 3 and EC 6 did not reduce total dry weight (DW) of any cultivars, except Hot Pak Yellow and Taishan Yellow. In conclusion, all marigold cultivars are moderately sensitive to salt. ‘Discovery Orange’, ‘Taishan Yellow’, ‘Discovery Yellow’, and ‘Taishan Gold’ were more tolerant than ‘Hot Pak Gold’, ‘Hot Pak Orange’, ‘Hot Pak Yellow’, and ‘Taishan Orange’.

Southern U.S. states such as Texas experience high temperatures and intense solar radiation during the summer production season. Use of shadecloth is common in Spain and other Mediterranean countries and is becoming popular with homeowners or small-acreage farmers in Texas. Little information is available on the applicability of using shadecloth on tomato (Solanum lycopersicum) and chili pepper (Capsicum annuum) in the warm climate of Texas. The effects of two shade nets differing in shading intensity on growth, chlorophyll fluorescence, and photosynthesis of ‘Celebrity’ tomato and ‘Sweet Banana’ chili pepper was investigated from May to Aug. 2014. Plants were grown in 50% shade, 70% shade, or full sun. Compared with the unshaded control, tomato grown in 50% shade had similar yield and shoot fresh and dry weight and less photochemical stress. The 50% shade reduced number and weight of unmarketable tomato fruit. Similar results were obtained with chili pepper except for lower numbers of marketable fruit. The 70% shade significantly reduced yield parameters of both tomato and chili pepper. Both 50% and 70% shadecloth reduced leaf temperatures of tomato and chili pepper with variable results in June and July. Growth index [(height + width 1 + width 2) ÷ 3] of tomato and chili pepper was the highest with 50% shade, the lowest with full sun, and intermediate with 70% shade. The maximum net photosynthetic rates (P_n) of tomato determined from a P_n to light response curve supported the results on growth and yield. However, the maximum P_n of chili pepper was higher in full sun treatment compared with 50% or 70% shade. The latter two were almost identical. This one growing season study indicated that shading at 50% benefits tomato and chili pepper production in west Texas by reducing heat stress; however, a shading percentage below 50% may be better.

Spirea (Spiraea sp.) plants are commonly used in landscapes in Utah and the intermountain western United States. The relative salt tolerance of seven japanese spirea (Spiraea japonica) cultivars (Galen, Minspi, NCSX1, NCSX2, SMNSJMFP, Tracy, and Yan) were evaluated in a greenhouse. Plants were irrigated with a nutrient solution with an electrical conductivity (EC) of 1.2 dS·m⁻¹ (control) or saline solutions with an EC of 3.0 or 6.0 dS·m⁻¹ once per week for 8 weeks. At 8 weeks after the initiation of treatment, all japanese spirea cultivars irrigated with saline solution with an EC of 3.0 dS·m⁻¹ still exhibited good or excellent visual quality, with all plants having visual scores of 4 or 5 (0 = dead, 1 = severe foliar salt damage, 2 = moderate foliar salt damage, 3 = slight foliar salt damage, 4 = minimal foliar salt damage, 5 = excellent), except for Tracy and Yan, with only 29% and 64%, respectively, of plants with visual scores less than 3. When irrigated with saline solution with an EC of 6.0 dS·m⁻¹, both ‘Tracy’ and ‘Yan’ plants died, and 75% of ‘NCSX2’ plants died. ‘Minspi’ showed severe foliar salt damage, with 32% of plants having a visual score of 1; 25% of plants died. ‘Galen’ and ‘NCSX1’ had slight-to-moderate foliar salt damage, with 25% and 21%, respectively, of plants with visual scores of 2 or less. However, 64% of ‘SMNSJMFP’ plants had good or excellent visual quality, with visual scores more than 4. Saline irrigation water with an EC of 3.0 dS·m⁻¹ decreased the shoot dry weight of ‘Galen’, ‘Minspi’, ‘SMNSJMFP’, and ‘Yan’ by 27%, 22%, 28%, and 35%, respectively, compared with that of the control. All japanese spirea cultivars had 35% to 56% lower shoot dry weight than the control when they were irrigated with saline irrigation water with an EC of 6.0 dS·m⁻¹. The japanese spirea were moderately sensitive to the salinity levels in this experiment. ‘Galen’ and ‘SMNSJMFP’ japanese spirea exhibited less foliar salt damage and reductions in shoot dry weight and were relatively more tolerant to the increased salinity levels tested in this study than the remaining five cultivars (Minspi, NCSX1, NCSX2, Tracy, and Yan).

Screening salinity-tolerant plants is usually time intensive and only applicable to a limited number of salinity levels. A near-continuous gradient dosing (NCGD) system allows researchers to evaluate a large number of plants for salinity tolerance with multiple treatments, more flexibility, and reduced efforts of irrigation. Rose of sharon (Hibiscus syriacus), ninebark (Physocarpus opulifolius), and japanese spirea (Spiraea japonica) were irrigated using an NCGD system with eight electrical conductivity (EC) levels ranging from 0.9 to 6.5 dS·m^–1. At 11 weeks after irrigation was initiated, there were no significant differences among EC levels in terms of visual score, growth index [(Height + Width 1 + Width 2)/3], stem diameter, number of inflorescences, and shoot dry weight (DW) of rose of sharon. However, the root DW, relative chlorophyll content (SPAD), and net photosynthesis rate (P_n) of rose of sharon decreased linearly as EC levels increased. Ninebark and japanese spirea had increased foliar salt damage with increasing EC levels. The growth index, stem diameter, number of inflorescences, shoot and root DW, SPAD, and P_n of ninebark decreased linearly as EC levels increased. The growth index and SPAD of japanese spirea decreased quadratically with increasing EC levels, but its stem diameter, number of inflorescences, shoot and root DW, and P_n decreased linearly with increasing EC levels. The salinity threshold (50% loss of shoot DW) was 5.4 and 4.6 dS·m^–1, respectively, for ninebark and japanese spirea. We were not able to define the salinity threshold for rose of sharon in this study. However, rose of sharon was the most salinity-tolerant species among the three landscape plants.

Commercial optical chlorophyll meters estimate relative chlorophyll content using the ratio of transmitted red light and near-infrared (NIR) light emitted from a red light-emitting diode (LED) and an NIR LED. Normalized difference vegetation index (NDVI) sensors have red and NIR light detectors and may be used to estimate chlorophyll content by detecting the transmitted red and NIR light through leaves. In this study, leaf chlorophyll content of ‘Torrey’ buffaloberry (Shepherdia ×utahensis) plants treated with 0 mm [zero nitrogen (N)], 2 mm (medium N), or 4 mm (ample N) ammonium nitrate for 3 weeks were evaluated using two commercial chlorophyll meters and NDVI sensors. The absolute chlorophyll content was determined using chlorophyll extraction. Our results showed that plants receiving ample N and medium N had decreased transmitted red light (i.e., greater absorption in red light). Measurements of optical chlorophyll meters, NDVI sensors, and chlorophyll extraction similarly showed that plants receiving medium N and ample N had greater leaf chlorophyll content than those receiving zero N. Relative leaf chlorophyll content estimated using NDVI sensors correlated positively with those from the chlorophyll meters (P < 0.0001; r² range, 0.56–0.82). Therefore, our results indicate that NDVI measurements are sensitive to leaf chlorophyll content. These NDVI sensors, or specialized sensors developed using similar principles, can be used to estimate the relative chlorophyll content of nursery crops and help growers adjust fertilization to improve plant growth and nutrient status.

The green industry has identified the use of biodegradable containers as an alternative to plastic containers as a way to improve the sustainability of current production systems. Field trials were conducted to evaluate the performance of four types of 1-gal nursery biocontainers [keratin (KR), wood pulp (WP), fabric (FB), and coir fiber (Coir)] in comparison with standard black plastic (Plastic) containers on substrate temperature, water use, and biomass production in aboveground nurseries. Locations in Kentucky, Michigan, Mississippi, and Texas were selected to conduct experiments during May to Oct. 2012 using ‘Green Velvet’ boxwood (Buxus sempervirens × B. microphylla) and ‘Dark Knight’ bluebeard (Caryopteris ×clandonensis) in 2013. In this article, we were focusing on the impact of alternative container materials on hourly substrate temperature variations and plant growth. Substrate temperature was on an average higher (about 6 °C) in Plastic containers (about 36 °C) compared with that in WP, FB, and Coir containers. However, substrate temperature in KR containers was similar to Plastic. Substrate temperature was also influenced by local weather conditions with the highest substrate temperatures recorded in Texas followed by Kentucky, Mississippi, and Michigan. Laboratory and controlled environment trials using test containers were conducted in Kentucky to evaluate sidewall porosity and evaporation loss to confirm field observations. Substrate temperature was similar under laboratory simulation compared with field studies with the highest substrate temperature observed in Plastic and KR, intermediate in WP and lowest in FB and Coir. Side wall temperature was higher in Plastic, KR, and FB compared with WP and Coir, while side wall water loss was greatest in FB, intermediate in WP and Coir, and lowest in plastic and KR. These observations suggest that the contribution of sidewall water loss to overall container evapotranspiration has a major influence on reducing substrate temperature. The porous nature of some of the alternative containers increased water use, but reduced heat stress and enhanced plant survival under hot summer conditions. The greater drying rate of alterative containers especially in hot and dry locations could demand increased irrigation volume, more frequent irrigation, or both, which could adversely affect the economic and environmental sustainability of alternative containers.