scholarly journals Cold Hardiness and Budbreak of Two Buckthorn Species

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1130C-1130
Author(s):  
J. Ryan Stewart ◽  
William R. Graves ◽  
Reid D. Landes

Can Carolina buckthorn (Rhamnuscaroliniana) persist north of its native habitat without becoming invasive? Its distribution (USDA zones 5b to 9b) suggests that genotypes vary in cold hardiness, and invasiveness of other Rhamnus sp. has been linked to unusually early budbreak each spring. Therefore, we investigated depth of cold hardiness and vernal budbreak of Carolina buckthorns from multiple provenances and made comparisons to the invasive common buckthorn (Rhamnus cathartica). Budbreak was recorded in Ames, Iowa, from 9 Apr. to 10 May 2002. Buds of common buckthorn broke earlier than those of Carolina buckthorn, and mulching plants of Carolina buckthorn hastened budbreak. Stem samples were collected in October, January, and April from a plot in Ames, Iowa (USDA zone 5a), of Carolina buckthorns from three provenances (Missouri, Ohio, and Texas) and of naturalized common buckthorns. A similar schedule was followed during the next winter, when two plot locations [Ames, Iowa, and New Franklin, Mo. (USDA zone 5b)], were compared, but Carolina buckthorns from only Missouri and Texas were sampled. Carolina buckthorn and common buckthorn survived midwinter temperatures as low as –21 °C and –24 °C, respectively. Provenance differences were minimal; Carolina buckthorns from Missouri were more hardy than those from Ohio and Texas only in April of the first winter. We conclude that its cold hardiness will permit use of Carolina buckthorn beyond where it is distributed in the southeastern United States. Delayed budbreak of Carolina buckthorn relative to that of common buckthorn may underscore the potential for Carolina buckthorn in regions with harsh winters and may lessen its potential to be as invasive as common buckthorn.

2006 ◽  
Vol 131 (3) ◽  
pp. 345-351 ◽  
Author(s):  
J. Ryan Stewart ◽  
William R. Graves ◽  
Reid D. Landes

Carolina buckthorn [Rhamnus caroliniana Walt. or Frangula caroliniana (Walt.) Gray] is an attractive and water-stress-resistant shrub or small tree distributed extensively in the southeastern United States that merits use in managed landscapes. Due to substantial climatic differences within its distribution (30-year normal midwinter minima range from 13 to -8 °C), selection among provenances based on differences in cold hardiness is warranted. Before selections are marketed, the potential of carolina buckthorn to be invasive also merits investigation. Ecological problems resulting from the introduction of Rhamnus L. species in the United States, most notably the dominance of R. cathartica L. (common buckthorn) over neighboring taxa, are due in part to early budbreak. Consequently, we investigated depth of cold hardiness and vernal budbreak of carolina buckthorn and common buckthorn. Stem samples of carolina buckthorn and common buckthorn collected in midwinter survived temperatures as low as -21 and -24 °C, respectively. Although the cold hardiness of carolina buckthorns from Missouri was greater than that of carolina buckthorns from Ohio and Texas on 2 Apr. 2003, there were no differences in cold hardiness of stems from Missouri and Texas on all three assessment dates in the second experiment. All plants survived at both field locations except for the carolina buckthorns from southern Texas planted in Iowa, which showed 0% and 17% survival in 2003 and 2004, respectively. Budbreak of both species with and without mulch in Ames, Iowa, was recorded from 9 Apr. to 10 May 2002. Mean budbreak of common buckthorn was 5.7 days earlier than budbreak of carolina buckthorn, and buds of mulched carolina buckthorns broke 4.2 days earlier than did buds of unmulched carolina buckthorns. We conclude that the cold hardiness of carolina buckthorn is sufficient to permit the species to be planted outside of its natural distribution. Populations of carolina buckthorn in Ohio and Missouri should be the focus of efforts to select genotypes for use in regions with harsh winters. Phenology of its budbreak suggests carolina buckthorn will not be as invasive as common buckthorn, but evaluation of additional determinants of invasiveness is warranted.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541e-541
Author(s):  
Gregory L. Reighard ◽  
David R. Ouellette

Large fluctuations in annual peach production is a chronic problem in the southeastern United States. Winter and spring cold injury to flowers reduces the potential peach crop almost every year in the Southeast. A bloom delaying peach interstem has consistently delayed phenology in the Southeast, but its effect on bud hardiness is unknown. Nine varieties (650–1050 chill hours) budded to `Ta Tao 5' (P.I. 101667) interstems on Lovell rootstock or budded to only Lovell rootstock (i.e., controls) were sampled monthly from November or December to late February in 1996–97 and 1997–98 from an interstem test established in 1993 near Clemson, S.C. High-chill varieties such as `Contender', `Encore', and `Redhaven' were 1 to 2 °C more cold-hardy on interstem trees in late winter. General trends showed that varieties were slightly more cold-hardy on interstems in 1996–97, but no differences were observed from Nov.1997 through early Jan. 1998. Significant varietal differences in cold-hardiness were found on each sampling date, but no trends were observed.


2000 ◽  
Vol 18 (4) ◽  
pp. 230-233
Author(s):  
S.M. Scheiber ◽  
Carol D. Robacker ◽  
Orville M. Lindstrom

Abstract Twelve taxa of deciduous azalea were evaluated using laboratory procedures to determine hardiness of stems and flower buds. Rhododendron atlanticum, ‘My Mary’, ‘Nacoochee’, and ‘TNLV1’ exhibited the greatest stem cold hardiness, surviving to at least −29C ± 1 (−20F ± 2) in February 1996. Rhododendron oblongifolium exhibited the least stem cold hardiness, surviving to only −11C ± 1 (10F ± 2). All results were consistent with previous field studies. Except for R. viscosum and R. serrulatum, lowest survival temperatures for stems were analogous to reports available in the literature. Rhododendron viscosum and ‘My Mary’ had the lowest survival temperature recorded for flower buds, −23C ± 1 (−9F ± 2), in February 1998 and February 1999, respectively, though not significantly different than most other taxa examined. Lowest survival temperatures for flower buds varied from published accounts, with buds in the present study being less hardy than previously reported. Differences from published reports in the lowest survival temperatures of stems and flower buds are attributed to provenance, temperature fluctuations, cultural effects on the plants, and differences among freeze test protocols.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 898E-898
Author(s):  
Gena R. Silva ◽  
Frank B. Matta ◽  
James M. Spiers

Late spring frosts are a major concern to blueberry growers in the southeastern United States. Cold hardiness of flower buds (stages 4 to 6) was evaluated in three southern highbush blueberry cultivars (`Cooper', `O'Neal', and `Gulfcoast'). Differential thermal analysis (DTA) and tissue browning tests revealed that the critical temperature and ovary damage occurred at –11C in `Cooper', –12C in `O'Neal', and –13C in `Gulfcoast'.


2019 ◽  
Author(s):  
Jorge Noguera

This study was conducted to determine the effectiveness of a novel mind perception manipulation. Mind perception is currently theorized to be an essential aspect of a number of human social psychological processes. Thus, a successful manipulation would allow for the causal study of those processes. This manipulation was created in an attempt to explore the downstream impact of mind perception on the endorsement of conspiracy theories. Conspiracy theories are steadily becoming more and more prominent in social discourse. Endorsement of conspiracy theories are beginning to show real world ramifications such as a danger to human health (e.g., in the anti-vaccination movement). A sample of college students (valid N = 53) from a large rural institution in the southeastern United States participated for course credit. These participants completed a mind perception pretest, were randomly assigned to either the manipulation in question (in which participants are asked to consider the ‘mind’ of several targets and write their thoughts about them) or the control condition, and then they completed a posttest. The mixed ANOVA revealed that the interaction term between Time and Condition was not significant. Because the manipulation did not work, other analyses were aborted, in accord with the pre-registration. My Discussion focuses on the procedures and potential shortcomings of this manipulation, in an effort to lay the groundwork for a successful one.


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