St. augustinegrass [ Stenotaphrum secundatum (Walt.) Kuntz] is a warm-season, perennial grass species commonly used in the turfgrass industry for its superior shade tolerance and stoloniferous growth habit. However, winter survival is a major
Jennifer A. Kimball, Thomas G. Isleib, William C. Reynolds, Maria C. Zuleta, and Susana R. Milla-Lewis
S. Alan Walters
the midwestern United States, as they tend to have greater winter survival and higher yields compared with softneck types ( Bachmann, 2001 ; Rosen, et al., 2006 ). However, softneck types are also popular with growers, as these are often used to
St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] has low freezing tolerance and suffers winter injury in the southeastern United States. Laboratory methods have determined that the lethal cold temperature of St. Augustinegrass stolons and buds is between -4.5 °C and -7.7 °C. The field survival of St. Augustinegrass to winter freezing is poorly known because most field reports have been based on a single location experiencing a single winter minimum air temperature. The objective of the study was to assess the winter survival of St. Augustinegrass cultivars across a range of winter minimum air temperatures occurring in experimental plantings at 24 Florida counties, following a severe Arctic cold front that moved through Florida beginning 21 Dec. 1989. Except for two counties, the limit for St. Augustinegrass winter survival was a minimum air temperature between -6 °C and -9 °C. Based on a nonlinear estimate using a 3-parameter sigmoidal model (r 2 = 0.70, P < 0.0001), 50% survival of St. Augustinegrass would be predicted at -7.9 °C. Time since planting had no relationship with survival. Differences among St. Augustinegrass cultivars were observed at only two counties.
William F. Hayslett, P. R. Thangudu, and Sabrina Shaw
A field study was conducted at Tennessee State University's research station to evaluate the effect of hardwood bark mulch on the winter survival of garden mums. A randomized complete block design was used. Cultivars used were adorn, encore, grandchild, jackpot, legend, minnautumn, minnwhite and triump. At the end of the flowering season the tops were removed leaving a four inch stubble in the mulch. The number of mum plants that resumed growth the following spring were counted for each cultivar. There was a difference in the winter survival of the different cultivars as well as a significant difference in the mulch treated and the control. Grandchild and jackpot were most cold hardy followed by encore, minnwhite, minnautumn, triump, legend, and adorn. Grandchild and jackpot with four inches of hardwood bark mulch had an 88 percent survival while the control had a 44 percent survival. Adorn. had a 51 percent survival with four inches of mulch and a 20 percent survival in the control. This data shows that hardwood bark mulch holds a great potential for providing excellent winter protection for garden mums.
Fumiomi Takeda, Kathy Demchak, Michele R. Warmund, David T. Handley, Rebecca Grube, and Charles Feldhake
cultivars. Wildung and Sargent (1989a , 1989b) studied the effect of snow cover on winter survival and productivity of blueberries in Minnesota where extremely cold winter temperatures (−34 °F) occur. They concluded that the value of RC in the winter
Fumiomi Takeda and John Phillips
’ blackberry trained to the rotatable cross-arm trellis HortScience 38 373 376 Takeda, F. Demchak, K. Warmund, M.R. Handley, D.T. Grube, R. Feldhake, C. 2008 Row covers improve winter survival and production of western trailing ‘Siskiyou’ blackberry in the
Bruce A. Cunliffe
It is common practice to propagate grasses by division in the spring rather than the fall. This is particularly true of warm-season grasses. Production schedules for grasses do not often fit the general production pattern of other herbaceous perennial or woody crops. Five ornamental grass species were studied: Schizachyrium scoparium, Sporobolus heterolepsis, Calamagrostis × acutiflora `Karl Foerster', Miscanthus sinensis `Purpurascens', and Miscanthus sinensis `Variegatus'. Uniform divisions based on species were planted in 4-inch (480-ml) pots, #1 (2780-ml), and #2 (6240-ml) containers. Fall divisions were done between 28 Oct. and 10 Nov. 1997. Spring divisions occurred between 30 Apr. and 7 May 1998. The experiment is a randomized complete-block design blocking on pot size. All containers were over-wintered under the same cover of plastic, straw, and plastic. Plants were evaluated for post-winter survival and growth. Plants were given a visual rating (0-3) every 2 weeks to assess salability. Spring survival of fall divisions was 99% for S. scoparium, C. × acutiflora `Karl Foerster', and M. sinensis `Purpurascens'. M. sinensis `Variegatus', and S. heterolepsis each had ≈50% survival. Fall divisions reached a salable rating a minimum of 2 weeks ahead of spring divisions. These results indicate that some ornamental grass species may benefit from fall rather than spring handling.
Bradley H. Taylor and Dagmar Geisler-Taylor
The timing and concentration of dilute foliar sprays of gibberellic acid (GA3) were tested for their flower bud thinning effect during three consecutive years on two common cultivars of peach [Prunus persica (L.) Batsch.] grown in commercial culture under midwestern conditions. There was a strong trend for June sprays to minimize the total flower bud density (buds/cm shoot) of unbranched shoots on mature `Redhaven' and `Cresthaven' trees. The GA3 treatments applied between early July and late October did not reduce the total flower bud density. Increasing the concentration from 25 or 50 mg·L-1 to 200 mg·L-1 tended to decrease total flower bud density, especially when applied May through July. During the same period the GA3 treatments reduced total flower bud density of short shoots (<10 cm), but only about two-thirds as effectively as on long shoots. The `Redhaven' live flower density on trees treated in May, June or September was up to 2 times greater then the control in March following exposure to extreme fluctuations in winter temperatures to near critical lows in 1988 and 1989. Although 50 mg·L-1 GA3 applied in June 1989 reduced total flower bud density by 70%, it resulted in a live flower density only 35% lower than the control. The treatment induced 2.3 times greater survival of the total flower buds existing after thinning when winter temperatures gradually declined to critical levels. The increased live flower density caused by the GA3 sprays translated to a cropload 1.3 to 2.25 times greater than control. The length of neither fruiting quality shoots in the bearing canopy nor 1-year-old upright branched shoots in the top of trees (watersprouts) was appreciably affected by the GA3 applications. GA3 treatments at 100 and 200 mg·L-1 in late July and early August slightly delayed time of full bloom. Defoliation was delayed slightly by treatments applied in September and late July. Moderate doses of appropriately timed GA3 sprays reduced flower bud densities without adverse effects on winter survival, yield, defoliation or bloom time. Our results support the use of GA3 as a reliable peach thinning tool.
Kaitlyn M. Orde and Rebecca Grube Sideman
fruit production and high yields during the second year. Straw mulch or rowcover have been used for winter protection by researchers and growers in the region, who report that winter survival rates vary from poor to excellent, depending on cultivar and
Sophie Rochefort, Yves Desjardins, David J. Shetlar, and Jacques Brodeur
winter survival and competitiveness in a kentucky bluegrass sward. We initiated a research program to investigate the potential of overseeding endophytic turfgrasses in established lawns to reduce insect pest problems in the northeastern extremes of