Progress 10/01/11 to 09/30/14
Outputs
Target Audience: greenhouse and nursery herbaceous perennial plant producers, landscapers, garden centers, home gardeners Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? presentations, professional industry articles, website, social media (facebook) What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
One of the issues growers face during winter is the fluctuation of temperatures in greenhouses during sunny periods, warming considerably in day and dropping to quite cold at night. Previous studies with such fluctuating temperatures with two species showed differences between two species. Becky Shasta daisy only survived at higher subsequent freezing temperatures (-2 or -5C) no matter the deacclimation (warming daytime) treatment, while Route 66 coreopsis showed little effect from deacclimation treatment or subsequent freezing levels. Field studies have begun and will be continued for 3 genera, with reduced species after 5 years of trials with coralbells. For the latter, those with best survival and vigor for at least 3 years include Blackout, Dark Secret, Frosted Violet, Mocha, and Silver Lode. Among the 90 or more tested over various time periods, 22 other species rated acceptable to excellent over at least 3 years. Panicum grass trials are only becoming established, with replacement plants for many cultivars planted this past year. Of the 6 little bluestem cultivars, Blue Heaven has been the highest rated and most attractive in summer and fall after 2 growing seasons and winters. Over 90 coneflowers have been tested over the past 2 seasons, with 55% loss over the 2013-14 winter. Among the top rated to date at flowering time are Green Envy, Coconut Lime, Purity, Happy Star, paradoxa, Fragrant Angel, Prairie Splendor, and Alba. Only Purity, paradoxa, Happy Star and Alba did not need subsequent staking. There were 16 other cultivars that rated excellent at flowering. Those with worse habits, ending up with virtually all stems on the ground, were Coconut Lime and Hot Lava.
Publications
- Type:
Websites
Status:
Published
Year Published:
2014
Citation:
perrysperennials.info
- Type:
Journal Articles
Status:
Under Review
Year Published:
2015
Citation:
Influence of Soil Moisture on Perennial Hardiness, Journal of Environmental Horticulture
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Progress 10/01/12 to 09/30/13
Outputs
Target Audience: green industry professional, nursery growers, landscapers, home gardeners Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? grower consultations, articles for state industry newsletter, website, television, presentations What do you plan to do during the next reporting period to accomplish the goals? Based on these results, future studies will evaluate the effect of longer deacclimation periods up to 10 days. Field studies will provide ground corroboration of pot freezer studies.
Impacts
What was accomplished under these goals?
In January when plants have been shown in previous studies to have maximum hardiness, two perennial species (Becky Shasta daisy and Route 66 coreopsis) were exposed to various periods of deacclimation including 1, 3 or 5 days of 16C for 8 hours during the day, returning to 4C at night; or 3 days at 16C. There were insufficient plants of coreopsis for the 1 day treatment. Plants were then immediately placed at -2C for 2 days to freeze solid, then after 6 replicate plants were removed, remaining plants were subjected to controlled freezing temperatures of -5, -8, -11, and -14C for a half hour once they reached each, and then returned to a 3-5C greenhouse. In April, plant regrowth was assessed using a visual rating scale of 1-5 (1 = dead, 3-5 = increasing salable quality, specific traits assessed varying by cultivar). Such ratings have been shown in previous studies to be reflective of dry weights. For coreopsis, there were no significant difference among freezing temperatures after 3 days at 16C or 5 days of fluctuating temperatures. The only significant differences among temperature treatments from either the control (no prior deacclimation to freezing) or 3 days of fluctuating temperatures with non-saleable (rated less than 3) plants at -14C. This relatively new and popular coreopsis, from this study, appears both hardy to low temperatures and possible affected by several days of deacclimation only at the lowest (-14C) temperature exposure. Becky Shasta daisy had plants rated significantly lower after -8 and lower exposures after all deacclimation treatments, and from the control, with most plants dead or mostly so. Plants exposed to -5 rated lower in all cases (3 range) than those after -2C (4 to 5 range). Those at two treatments were significantly different between these two temperatures, however, this may be an artifact due to higher standard errors of the mean (0.2 compared to 0.1 for other treatments). This popular daisy, from this study, appears hardy to only -5C, with no differences among these deacclimation treatments at either -2 or -5C.
Publications
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: This study contributed to the knowledge of relative hardiness of 7 perennial species, 3 being coneflowers which are one of the currently most popular genera, both during mid-winter and late winter when perennials begin to come out of dormancy. Results are being shared with industry both in their publications and presentations, and on the author's Perry's Perennial Pages website. Based on these results, future studies will investigate the effect on hardiness of midwinter deacclimation and reacclimation temperatures, as well as relative hardiness of other popular perennial species. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: ornamental perennial growers, retailers, home gardeners PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Many retail and wholesale nurseries grow herbaceous perennials, and many such growers in northern climates need to successfully overwinter plants either in production, or held from the previous year, in overwintering structures such as greenhouses. They need to know what low temperatures plants will tolerate and survive, in order to adjust their heating and culture accordingly. Such results will result in significant economic savings in both fuel and plant losses. In many cases perennials may be overwintered at lower temperatures, with lower heat inputs, thus saving not only fuel but lessening the impact of burning excess fuel on global warming. In early January and late February, coneflower plants were exposed to controlled freezing temperatures of -2, -5, -8, -11, and -14C and then returned to a 3-5C greenhouse. Four other perennials were similarly frozen in January only. In April, plant regrowth was assessed using a visual rating scale of 1-5 (1 = dead, 3-5 = increasing salable quality, varying by cultivar). Such ratings have been shown in previous studies to be reflective of dry weights. In January, both Pixie Meadowbrite coneflower and Sherwood Purple creeping phlox showed no differences among temperatures, hardy to the lowest one. Pixie Meadowbrite plants were still salable (rated 3.0 or above) after freezing in February to all but the lowest temperature. Pica Bella coneflower plants were salable after January exposure to -8C and only down to -5C in February. White swan coneflower was the least hardy perennial tested, salable only to -5C in January and with no plants salable after February freezing. In the January freezing, Raspberry Regal coralbells were salable to -11C, Raspberry Wine bee balm to -5C , and Glowing Embers chrysanthemum to -5C as well.
Publications
- No publications reported this period
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