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Lane Greer and John M. Dole

Six defoliants were applied in fall and tested for their efficacy in preharvest defoliation of field grown curly willow (Salix matsudana `Tortuosa'), american bittersweet (Celastrus scandens), and american beautyberry (Callicarpa americana). Defoliants included acetic acid, chelated copper, crop oil concentrate (COC), ethephon, dimethipin plus COC, pelargonic acid, and a tap water control. For chelated copper, a concentration of 800 mg·L–1 was most effective at promoting defoliation, providing 100% defoliation of american bittersweet and 76% defoliation of american beautyberry. For curly willow and american beautyberry, all concentrations of dimethipin produced good or excellent defoliation. Increasing concentrations of ethephon from 200 to 2500 mg·L–1 increased defoliation from 0% to 67%. Pelargonic acid was not effective at promoting defoliation of woody plants at the concentrations used. In an experiment conducted during spring using containerized curly willow, irrigation was stopped for 0, 3, or 6 days before defoliants were applied, but none of the irrigation treatments promoted defoliation. In a postharvest study using cut curly willow, stems were held in distilled water at 5, 20, or 35 °C for 1, 3, 5, or 7 days. Holding cut stems of curly willow at 20 °C promoted 68% defoliation, compared to 53% or 28% for 5 or 35 °C, respectively.

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Alicain S. Carlson and John M. Dole

The effects of various postharvest treatments on cut stems of ‘Coral’ and ‘Sparkling Burgundy’ pineapple lily (Eucomis sp.) were evaluated to determine best postharvest handling practices. The use of a commercial hydrator, holding solution, or both significantly reduced vase life for ‘Coral’; the deionized (DI) water control had the longest vase life. ‘Sparkling Burgundy’ vase life was significantly reduced to 29.9 days when both a commercial hydrator and holding solution were used as compared with 50.3 days when DI water was the hydrator used with the commercial holding solution. The use of a bulb-specific preservative reduced vase life of ‘Coral’ to 43.8 days, while the DI water control had a vase life of 66.4 days, and commercial holding solution was intermediate at 56.8 days. A 10% sucrose pulse reduced vase life to 46.9 days compared with the 0% sucrose control (58.9 days) and the 20% sucrose concentration (62.5 days), which were not significantly different. The use of floral foam and/or 2% or 4% sucrose concentrations plus isothiazolinone reduced vase life significantly to an average of 11.1 days. The vase life of stems cold stored at 2 °C for 1 week (37.7 days) was not significantly different from the unstored stems (43.0 days), while longer storage times up to 3 weeks significantly reduced vase life. The use of hydrating solution pretreatments before and holding solution treatments during 4 days of cold storage had no significant effect on vase life. ‘Sparkling Burgundy’ stems harvested with 100% of the florets open had the longest vase life of 51.2 days compared with 38.4 days when 1% of the florets were open. Vase life was unaffected by exogenous ethylene exposure up to 1 ppm for 16 hours. For best postharvest quality, ‘Coral’ and ‘Sparkling Burgundy’ pineapple lily should be harvested when at least 50% of the florets are open, held in plain water without preservatives, and stored for no more than 1 week (wet or dry) at 2 °C.

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Frank Blazich Jr. and John M. Dole

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Todd J. Cavins and John M. Dole

Campanula medium L. `Champion Blue' and `Champion Pink' and Lupinus hartwegii Lindl. `Bright Gems' were grown in 8- or 16-h initial photoperiods, transplanted when 2-3, 5-6, or 8-9 true leaves developed, and placed under 8-, 12-, or 16-h final photoperiods. The lowest flowering percentage for `Champion Blue' (<1%) and `Champion Pink' (16%) resulted from plants grown in the 8-h photoperiod continuously. One hundred percent flowering occurred when Campanula were grown in the 16-h final photoperiod, indicating that `Champion Blue' and `Champion Pink' are long-day plants. Plants grown initially in the 8-h and finished in the 16-h photoperiod had the longest stems. Stem diameter was generally thickest for plants grown in the 8-h compared with the 16-h initial photoperiod. However, the 8-h initial photoperiod delayed anthesis compared with the 16-h initial photoperiod. `Champion Blue' and `Champion Pink' plants transplanted at the 2-3 leaf stage from the 16 hour initial to the 8-h final photoperiod had flowering percentages of 64% and 63%, respectively; however, when transplanted at the 8-9 leaf stage, plants were fully mature and 100% flowering occurred indicating that all plants were capable of flowering. In year 2, plants receiving high intensity discharge (HID) supplemental lighting during the 16-h initial photoperiod reached anthesis in 11 fewer days compared with plants not receiving HID supplemental lighting. High profits were obtained from Campanula grown in the 8-h initial photoperiod and transferred at 5-6 true leaves into the 16-h final photoperiod. Lupinus hartwegii plants had a high flowering percentage (96% to 100%) regardless of photoperiod or transplant stage. The 16-h final photoperiod decreased days to anthesis compared with the 8- or 12-h final photoperiod indicating that L. hartwegii is a facultative long-day plant. Increasing length of final photoperiod from 8- to 16-h increased stem length. Juvenility was not evident for Lupinus in this study. In year 2, Lupinus cut stems were generally longer and thicker when given HID supplemental lighting, especially when grown in the 8- or 12-h final photoperiod. Supplemental lighting also reduced days to anthesis. Highest profits were generally produced from Lupinus plants grown with supplemental HID lighting (during the initial photoperiod) until 8-9 true leaves had developed.

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Alicain S. Carlson and John M. Dole

The effects of production temperature and transplant stage on stem length and caliper of cut stems and postharvest treatments on vase life of ‘Esprit’ penstemon (Penstemon grandiflorus) were examined. Plugs transplanted with eight to nine sets of true leaves had a longer stem length (64.3 cm) at harvest than those transplanted with two to three sets (57.7 cm) or five to six sets (60.8 cm). Time to flowering from transplant shortened as production temperature increased and when transplants had a greater number of true leaves. The addition of 2% or 4% sucrose with 7 ppm isothiazolinone as a vase solution resulted in the longest vase life (9.4 days) of all treatments compared with the control (4.5 days). A holding solution increased vase life to 7.0 days for Floralife holding solution and 5.9 days for Chrysal holding solution from the 4.3 days control, although hydrating solutions and preservative brand had no effect. The use of floral foam or antiethylene agents, ethylene exposure, or sucrose pulses also had no effect on vase life. Extended cold storage lengths either wet or dry for 2 or 3 weeks caused vase life to decrease to 2.0 days when compared with 5.6 days for the unstored control and 7.6 days for 1 week storage. ‘Esprit’ penstemon may be suitable for greenhouse production and has acceptable potential as a locally grown specialty cut flower.

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Alicain S. Carlson and John M. Dole

Pineapple lily (Eucomis hybrids) has long, striking inflorescences that work well as a cut flower, but information is needed on proper production methods and postharvest handling protocols. The objective of this study was to determine the effects of bulb storage temperature and duration, production environment, planting density, and forcing temperatures on cut flower production of ‘Coral’, ‘Cream’, ‘Lavender’, and ‘Sparkling Burgundy’ pineapple lily. Stem length was greater in the greenhouse than the field and at the low planting density. Plants in the field at the low planting density had the shortest stem length for ‘Coral’ and ‘Cream’, but still produced marketable lengths of at least 30 cm. Planting density did not affect ‘Lavender’ and ‘Sparkling Burgundy’ stem length or number of marketable stems. The productivity (number of marketable stems per bulb) was affected only by planting density for ‘Coral’ and planting environment for ‘Cream’. Differences in stem quality and productivity differed for each cultivar and planting density over the next two seasons. The productivity of ‘Coral’ increased significantly from year to year, while the productivity of ‘Cream’ only significantly increased between the first and second years. The low planting density resulted in slightly more stems per bulb for ‘Coral’ over the next two seasons. Emergence after bulb storage treatments was highest in treatments where the bulbs were not lifted from the substrate and were subsequently grown at 18 °C. Bulbs grown in the warmest (18 °C) production temperature flowered soonest and had shorter stem lengths. For earliest flowering, bulbs should be stored in substrate in cool temperatures of at least 13 °C and forced at warm temperatures of at least 18 °C.

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Paul B. Redman and John M. Dole

The postharvest attributes of six specialty cut flower species were studied. First year results indicate that Achillea filipendulina `Coronation Gold' had a vase-life of 10.7 days in deionized water (DI) and can be stored one week at 1.7°C and shipped for one day. Buddeleia davidii (Butterfly Bush) had a vase life of 3.8 days in DI water and tolerated two weeks of cold storage and two days of shipping. Celosia plumosa `Forest Fire' (Plume Celosia) had a vase-life of 5.9 days in DI water and tolerated 2 days of shipping. Cercis canadensis (Redbud) had a vase-life of 9 days in DI water and tolerated one day of shipping. Echinacea purpurea `Bright Star' (Purple Coneflower) had a vase-life of 4.6 days in DI water and tolerated 2 weeks of storage and five days of shipping. Helianthus maximilianii (Maximillian Sunflower) had a vase-life of 6.3 days in DI water and tolerated one week of storage. In addition, silver thiosulfate and 8-hydroxyquinoline citrate increased vase-life of Buddeleia davidii, Celosia plumosa, Echinacea purpurea, and Helianthus maximilianii.

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John M. Dole, Paul Fisher, and Geoffrey Njue

Several treatments were investigated for increasing vase life of cut `Renaissance Red' poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch.) stems. A vase life of at least 20.6 days resulted when harvested stems were placed directly into vases with 22 °C deionized water plus 200 mg·L-1 8-HQS (the standard floral solution used) and 0% to 1% sucrose without floral foam. Maturity of stems at harvest, ranging from 0 to 4 weeks after anthesis, had no effect on vase life or days to first abscised leaf. Pretreatments immediately after harvest using floral solution heated to 38 or 100 °C, or 1 or 10-min dips in isopropyl alcohol, had no effect, whereas 24 hours in 10% sucrose shortened vase life by 6.4 days and time to first abscised cyathium by 4.5 days. Stem storage at 10 °C decreased vase life, particularly when stems were stored dry (with only 0.8 days vase life after 3 weeks dry storage). Increasing duration of wet storage in floral solution from 0 to 3 weeks decreased vase life from 21.5 to 14.6 days. Placing cut stems in a vase containing floral foam decreased time to first abscised leaf by 3.7 to 11.6 days compared with no foam. A 1% to 2% sucrose concentration in the vase solution produced the longest postharvest life for stems placed in foam but had little effect on stems not placed in foam. A 4% sucrose concentration decreased vase life compared with lower sucrose concentrations regardless of the presence of foam. Holding stems in the standard floral solution increased vase life and delayed leaf abscission compared with deionized or tap water only, with further improvement when stem bases were recut every three days. Commercial floral pretreatments and holding solutions had no effect on vase life and days to first abscised cyathium but delayed leaf abscission.

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John M. Dole and Michael A. Schnelle

Oklahoma floriculture producers, ornamental-horticulture retailers, mass-market retailers, and cut-flower wholesalers were surveyed to compare and contrast the industry in terms of attitudes towards their products and problems. Overall, attitudes of all four segments of the industry were neutral to negative on potted flowering plants, but were positive to neutral on bedding and foliage plants. However, producers were slightly negative concerning the postharvest life of bedding plants. While cut-flower wholesalers had a positive attitude concerning cut flowers, ornamental-horticulture retailers and mass-marketers tended to be neutral to negative. In particular, retailers and mass-marketers believed that cut flowers were too expensive and too short-lived. Floral preservatives were used by 82% of ornamental-horticulture retailers, while only 19% of mass-market retailers used preservatives. All cut-flower wholesalers used preservatives. Capital availability and market demand were the factors most limiting expansion for producers and ornamental-horticulture retailers; whereas mass-market firms listed competition as their most limiting factor.

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John M. Dole and Harold F. Wilkins

The free-branching poinsettia (Euphorbia pulcherrima Willd. ex. Klotzsch) cultivar Annette Hegg Brilliant Diamond (BD) contained a free-branching agent that was graft-transmissible to the restricted-branching cultivar Eckespoint C-1 Red (CR). CR plants were transformed by the agent regardless of whether BD plants were used as scion or stock, indicating that the agent moved basipetally and acropetally through the graft union. The agent was repeatedly transmitted to a CR plant by serial grafting with a free-branching poinsettia plant. A minimum of 10 days contact through grafting was required for BD plants to transmit the agent to CR plants. Percentage of CR plants exhibiting the free-branching characteristic increased from 0% for < 10 days of graft contact with BD plants to 100% after 30 days.