Screening Perennial Bedding Plants for Response to Plant Growth Regulators

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446e-447
Author(s):  
Joyce G. Latimer ◽  
Paul A. Thomas

Perennial bedding plant species were tested for response to single treatments of Sumagic (0, 15, 30, 45, or 60 ppm), Bonzi (0, 40, 80, 120, or 160 ppm), Cycocel (0, 750, 1500, 2250, or 3000 ppm) or B-Nine (5000 ppm, applied twice) applied during greenhouse production in Spring 1997. Plant height of both Chrysanthemum parthenium and Malva alcea had a quadratic response to Sumagic and Bonzi rates, with excessive height reductions at the lowest application rates at 4 weeks after treatment. All rates of Cycocel reduced plant height of C. parthenium and M. alcea by 33% and 40%, respectively. These species did not establish in the landscape. Verbena bonariensis was moderately responsive to Sumagic and Bonzi, but not Cycocel. Application rates of 15 and 30 ppm Sumagic or 160 ppm Bonzi provided moderate height control without landscape persistence beyond 4 weeks after planting. Leucanthemum × superbum `Alaska' was responsive to Sumagic and Bonzi, but not Cycocel or B-Nine. Rates of 15 ppm Sumagic or 40 ppm Bonzi provided moderate control without landscape persistence. Plant height of Monarda didyma `Blue Stocking' had a linear response to Sumagic and Bonzi rates. Plant height of Rudbeckia fulgida var. Sullivantii `Goldstrum' was reduced by Bonzi and Sumagic but not B-Nine or Cycocel, with recommended rates of 30 to 40 ppm Sumagic or 160 ppm Bonzi. Treatment of Sedum × `Autumn Joy' with Sumagic resulted in excessive landscape persistence of growth retardation at all rates, but Sedum was not responsive to Cycocel. Veronica alpina `Sunny Border Blue' was responsive to all rates of Cycocel, but growth retardation persisted through 12 weeks after planting.

1992 ◽  
Vol 10 (4) ◽  
pp. 232-235
Author(s):  
David R. Brown ◽  
D. Joseph Eakes ◽  
Bridget K. Behe ◽  
Charles H. Gilliam

Abstract Moisture stress was compared to B-nine (daminozide) as a method of height control for annual bedding plant transplants. Three plant species, ‘Big Boy’ tomato, ‘California Wonder’ pepper and ‘Janie Gold’ marigold, were grown in 132 cm3 (8.05 in3) cell packs containing one of 2 commercial media, Fafard #3 or Pro-Mix BX. Treatments included moisture stress (MS), 2 concentrations of B-nine (2500 ppm applied twice and 5000 ppm once), and an untreated control. Method of height control and medium type had an interactive influence on height for each of the 3 species. Moisture stress tomato and marigold were shorter in the Fafard #3 medium compared to those in the Pro-Mix BX medium. Regardless of medium, MS tomato and marigold transplants were shorter or similar in size to the most effective B-nine treatment, 2500 ppm applied twice. Moisture stress and the B-nine treatments for pepper plants grown in the Fafard #3 medium reduced plant height similarly compared to the controls. However, when pepper plants were grown in the Pro-Mix BX medium, only B-nine treatments reduced plant height compared to the controls. Treatments producing short plants did not reduce node number, hence plants appeared fuller than treatments with tall plants. Shoot dry weights for MS tomato and marigold were less than those of plants receiving the other height control treatments, regardless of medium type. Plants of all 3 species grown in the Fafard #3 medium had less shoot dry weight than Pro-Mix BX plants across the 4 height control treatments.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 757D-758
Author(s):  
Stanislav Magnitskiy* ◽  
Claudio Pasian ◽  
Mark Bennett

Regulation of excessive vegetative growth is of importance in both field and bedding plant production. The goal of the study was to evaluate the effect of preplant seed soaking in growth regulators on the growth control of floricultural (verbena, salvia, pansy, marigold, celosia) and agronomic (cucumber, dill) crops. Seeds were soaked in water solutions of growth regulators of different concentrations ranging according to the crop from 50 to 1000 mg·L-1 for paclobutrazol, 1 to 10 mg·L-1 for uniconazole, 10 to 200 mg·L-1 for ancymidol, 100 to 5000 mg·L-1 for chlormequate chloride and dried at 20 °C for 24 h prior to sowing into plugs. In the first experiment, seeds of verbena, salvia, pansy, and dill soaked for 5 minutes in 50 mg·L-1 paclobutrazol solutions produced seedlings that were up to 43, 18, 30, and 22% shorter than the controls, respectively. Increased paclobutrazol concentrations and soaking time generally corresponded to a greater reduction of plant height, as well as delays and reduction in seedling emergence of all crops, except cucumber. In the second experiment, growth of marigold plugs from seeds soaked in 5 mg·L-1 uniconazole or 60 mg·L-1 ancymidol solutions during 45 min was associated with 23% or 6% plant height reduction, respectively. Soaking of marigold seeds in the solutions of chlormequate chloride did not significantly affect seedling growth. Increasing time of seed soaking in growth regulator solutions did not influence emergence of marigold seedlings. The height of celosia seedlings was only slightly reduced by soaking seeds in the solutions of all studied growth regulators. Results indicate that seed treatments with growth regulators might be useful in growth control of selected bedding plants.


1998 ◽  
Vol 8 (4) ◽  
pp. 535-539 ◽  
Author(s):  
Robert Berghage

Temperature management has emerged as an important tool for plant height control in greenhouse production systems. This is particularly important in vegetable transplant production where chemical controls for plant height are limited or not legal. Plant height is a function of the number of nodes and the length of each internode, and both are strongly influenced by greenhouse temperatures. Node number, or formation rate, is primarily a function of the average greenhouse temperature, increasing as the average temperature increases. Internode length is strongly influenced by the relationship between the day and night temperature, commonly referred to as DIF (day temperature - night temperature). As DIF increases, so does internode length in most plant species studied. Although the nature and magnitude of temperature effects vary with species, cultivar, and environmental conditions, these two basic responses can be used to modify transplant growth. Although data are limited, controlling transplant height with temperature does not appear to adversely influence plant establishment or subsequent yield.


1998 ◽  
Vol 16 (3) ◽  
pp. 138-142
Author(s):  
Joyce G. Latimer ◽  
Ronald D. Oetting

Abstract Conditioning treatments were evaluated for effects on growth of bedding plants during greenhouse production and carryover effects on plant performance in the landscape. Treatments included two fertilization regimes using a complete water soluble fertilizer applied three times/week at 500 ppm N, designated ‘high N’, or at 50 ppm N, designated the ‘low N’ treatment. Other treatments included: ebb and flow irrigation, drought stress for up to 2 h wilt/day, 5000 ppm B-Nine (daminozide), 45 ppm Bonzi (paclobutrazol; 180 ppm on columbine), and brushing (40 strokes twice daily). Unless otherwise noted all plants, including controls, were maintained well-irrigated and fertilized with 250 ppm N three times/week. Marigolds and New Guinea impatiens grown under low N during greenhouse production exhibited reduced plant height and width relative to control plants at 4 weeks after planting (WAP) in the landscape. Plant quality ratings of all species conditioned with low N were lower than those of controls 2 and 4 WAP. Plant height of New Guinea impatiens conditioned with high N was greater than that of controls 4 WAP in the landscape. Marigolds subjected to drought in the greenhouse were still shorter than controls 2 and 4 WAP. Persistent height reductions in the landscape in response to B-Nine were observed in ageratum 2 and 4 WAP and to Bonzi in New Guinea impatiens through 8 WAP. Brushing reduced the height of all species except ageratum in the greenhouse, but had no carryover effect on plant growth in the landscape. At 4 weeks after treatment, plant height of columbine treated with low or high N, drought, brushing, or B-Nine was reduced relative to controls, but all plants were similar in size in the landscape.


Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 589-589
Author(s):  
P. M. Prichard ◽  
M. K. Hausbeck ◽  
R. D. Heins

Plant height can be regulated by manipulation of day (DT) and night temperatures (NT). Traditionally, commercial flower crops are grown with a DT higher than the NT, which results in greater internode length than when the regimen is reversed. Because temperature manipulation is a popular height-control tool among growers, the influence of DT/NT regimens of 16/16, 19/19, 22/22, 16/19, 19/22, 16/22, 19/16, 22/19, and 22/16°C on foliage susceptibility to Botrytis cinerea was investigated. After a minimum 3-week temperature treatment, seed geraniums (Pelargonium × hortorum), petunias (Petunia × hybrida), and impatiens (Impatiens wallerana) were inoculated with 2.7 × 105 B. cinerea conidia per ml of water and incubated at 20°C for the duration of the experiment. When averaged over two experiments, the maximum proportion of geranium, petunia, and impatiens foliage infected was 81.5, 35.5, and 27.0%, respectively. The maximum proportion of leaves supporting sporulating B. cinerea was 59.5% for geraniums, 25.5% for petunias, and 5.5% for impatiens. Area under the disease progress curve data indicated that susceptibility of bedding plant foliage was not influenced by the difference in DT/NT regimens. Results suggest that growers that use higher NT than DT to limit plant height do not increase host susceptibility to B. cinerea. However, more rigorous disease management strategies are needed for production of seed geraniums than for petunias or impatiens.


HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 593B-593
Author(s):  
Joyce G. Latimer ◽  
Paul A. Thomas

Nine perennial bedding plants were screened for responsiveness to the plant growth retardant, Sumagic (uniconazole-P). Two weeks after planting, plugs were treated with one foliar spray of Sumagic at 0, 40, 80, 120, or 160 ppm at the label-recommended volume. Plant growth of Gaillardia grandiflora `Goblin' was not reduced by Sumagic. Height of Achillea × `Moonshine' was reduced 8% to 12% at 4 weeks after treatment (WAT), and the reduction persisted through 8 weeks after planting (WAP) to the landscape. Phlox paniculata `Joliet' responded linearly to increasing Sumagic rate with a maximum height reduction of 32% at 160 ppm. Coreopsis grandiflora `Sunray', Rudbeckia fulgida var. Sullivantii `Goldsturm' and Monarda didyma `Blue Stocking' responded significantly to Sumagic with 30% to 60% height reductions at 4 WAT, but no persistent effects at 8 WAP. Height of Veronica alpine `Goodness Grows' was reduced 32% to 68% at 4 WAT, but all Sumagic rates resulted in persistent reductions in plant height at 12 WAP. Plant height of Alcea rosea mix and Echinacea purpurea were excessively reduced (up to 79%) at 4 WAT, but there were no persistent effects on height of Alcea in the landscape. All rates of Sumagic resulted in persistent reductions in height of Echinacea at 8 WAP, but only plants treated with 120 and 160 ppm Sumagic were still significantly shorter than controls at 12 WAP


HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 856-864 ◽  
Author(s):  
Yanjun Guo ◽  
Terri Starman ◽  
Charles Hall

This study analyzed the effects of two ranges of drying down of substrate moisture content (SMC) before re-watering on plant growth and development, postproduction quality, and economic value of bedding plants grown in 1.67-L containers during greenhouse production. The two SMC treatments were wide-range (WR) SMC (WR-SMC) for dry-down from container capacity (CC) of 54% SMC dried down to 20% SMC or narrow-range (NR) SMC (NR-SMC) for dry-down from CC of 54% SMC dried down to 40% SMC. Six bedding plant cultivars were used [Solenostemon scutellarioides ‘French Quarter’ (coleus); Petunia ×hybrida ‘Colorworks Pink Radiance’ (petunia); Lantana camara ‘Lucky Flame’ (lantana); Impatiens ×hybrida ‘Sunpatiens Compact Hot Coral’ (SCC); ‘Sunpatiens Spreading Lavender’ (SSL) (impatiens); and Salvia splendens ‘Red Hot Sally II’ (salvia)]. Shoot dry weight was reduced with WR-SMC on petunia, lantana, impatiens SCC, and salvia at the end of production. With WR-SMC, the petunia and impatiens SCC root ball coverage percentages were greater on the bottom of the container, whereas those of impatiens SSL and salvia were reduced. The WR-SMC increased petunia postproduction quality by increasing the flower number. Lantana and impatiens SCC inflorescence/flower and/or bud number were reduced with WR-SMC. The impatiens SSL flower number was unaffected by SMC treatment. Salvia grown with WR-SMC had increased postproduction quality. WR-SMC reduced postproduction water potential in petunia, lantana, and coleus, suggesting that plants with WR-SMC during production were acclimated to reduced irrigation administered during postproduction. WR-SMC saved labor due to less frequent watering and overhead-associated costs due to reduced bench space, with the exception of coleus and impatiens SSL, which used the same bench space as NR-SMC. Considering production and/or postproduction quality, using WR-SMC during greenhouse production is beneficial as an irrigation method for coleus, petunia, impatiens SSL, and salvia, but not for impatiens SCC or lantana grown in 1.67-L containers.


2018 ◽  
Vol 28 (4) ◽  
pp. 445-449
Author(s):  
Shawn D. Lyons ◽  
William B. Miller ◽  
H. Christian Wien ◽  
Neil S. Mattson

When grown in containers, pineapple lily (Eucomis sp.) can produce excessively long foliage and tall scapes, particularly in cultivars with tall pineapple lily (Eucomis comosa) parentage. Height control, through the use of plant growth regulators (PGRs), is necessary to improve crop quality of potted pineapple lily. In year 1 of these trials, bulbs of cultivars Reuben, Tugela Jade, and Tugela Gem were given substrate drenches of flurprimidol or paclobutrazol, each at 2, 4, or 6 mg per 6-inch pot. Drenches were applied at the “visible inflorescence” stage. As concentration increased, scapes were generally shorter in all cultivars for both PGRs, but there was no effect on foliage length or production time. At the rates tested, the reduction in scape length was insufficient to produce marketable plants of the three cultivars. In the second year, substrate drenches were applied at an earlier stage than in year 1, at “leaf whorl emergence,” when shoots were about 7 cm tall. The PGR treatments were notably more effective at controlling plant height in the second year. As concentration increased, scape and foliage length was reduced relative to the controls in all three cultivars for both PGRs. For all cultivars, inflorescence leaning and toppling were sharply reduced at all application rates compared with untreated controls. The reduction in plant height observed in year 2, particularly in plants treated with 4 or 6 mg/pot, resulted in plants with compact scapes and foliage proportional with their 6-inch containers.


1993 ◽  
Vol 11 (1) ◽  
pp. 17-19
Author(s):  
Janet C. Henderson-Cole ◽  
Michael A. Schnelle

Abstract Four bedding plant species, rose periwinkle, petunia, geranium, and scarlet salvia; four ground cover cultivars, golden Japanese barberry, common periwinkle, Bowles periwinkle, and greater periwinkle; and pots seeded with two weed species, crabgrass or pigweed were sprayed with 0, 1.1 or 4.5 kg ai/ha (0, 1.0 or 4.0 lb/A) prodiamine (Barricade) or 2.2 kg ai/ha (2.0 lb/A) oxadiazon (Ronstar). Heights or dry weights or both of all bedding plant species decreased linearly with increasing prodiamine (Barricade) application rates. Ground covers were not affected by oxadiazon (Ronstar) or prodiamine (Barricade) except for a reduction in root dry weight of common periwinkle with prodiamine (Barricade) applications. Crabgrass and pigweed were completely controlled by prodiamine (Barricade) throughout the growing season, but oxadiazon (Ronstar) lost its effectiveness after three months.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1144a-1144 ◽  
Author(s):  
Jodi Benson ◽  
John Kelly

Height control is a major concern when growing bedding plants. Growth regulating chemicals are often applied to regulate height of bedding plant species. However, reductions in plant height have been observed when plants were grown under light with a high ratio of red to far red light. Light passing through clear double walled, acrylic panels filled with copper sulfate solution has a high red to far red ratio. This work examined the effect of growing tomatoes, peppers, pansies, petunias, geraniums, and impatiens under panels filled with 4, 8, and 16 percent copper sulfate solution. Plants were grown for approximately 3 weeks in cell packs, then data were taken on plant height, number of leaves, leaf area, fresh and dry weight, and chlorophyll content. Significant reductions in height (40-66%) were achieved by growing bedding plants under any of the copper sulfate concentrations.


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