, 1988 ; Marshall and Gilman, 1998 ; Stabler and Martin, 2000 ). Table 1. Shoot and root dry biomass for Ilex cornuta ‘Burfordii Nana’ irrigated every 2, 4, or 8 d averaged over eight planting dates over a 2-year period in USDA hardiness zones
Christine L. Wiese, Amy L. Shober, Edward F. Gilman, Maria Paz, Kimberly A. Moore, Sloane M. Scheiber, Meghan M. Brennan, and Sudeep Vyapari
Sloane M. Scheiber, Maria Paz, Edward F. Gilman, Kimberly A. Moore, Sudeep Vyapari, and Richard C. Beeson Jr.
Landscape water consumption has become a prime target for water conservation and regulation. Imposing water restrictions during landscape establishment is detrimental to plants that have not developed sufficient root systems to compensate for transpirational water losses. Generally, municipalities regulate irrigation frequency but not application rate. Application frequency affects establishment rates of shade trees, but the effects on shrub establishment are not well documented. This study evaluated three irrigation frequencies during establishment of Ilex cornuta `Burfordii Nana' and Viburnum odoratissimumin a landscape. To simulate maximum stress, both species were transplanted into field plots in an open-sided, clear polyethylene covered shelter. Each species was irrigated either every 2, 4, or 7 days, and received 9 L of water per plant per event. Predawn, midday, and dusk water potentials were recorded at 28-day intervals and cumulative stress intervals calculated. Water potentials were taken the day prior to irrigation (maximum stress day) and the day of irrigation (minimum stress). Growth indices were also recorded. As days after transplant (DAT) increased, significant declines in cumulative water stress of Ilexwere found among treatments on the day of maximum stress. The 7-day treatment declined at a faster rate than the other treatments tested. No differences were found for Viburnum. No significant differences were found on the day of irrigation as DAT increased. Differences in canopy size were not significant among treatments for either species.
Patricia R. Knight, D. Joseph Eakes, Kenneth M. Tilt, and Charles H. Gilliam
Stem cuttings of Ilex cornuta `Burfordii Nana' and Ilex × `Nellie R. Stevens', were direct stuck into cell pack, rose pot, quart pot, and trade gallon containers on March 4, 1991. Ten weeks and again at twenty weeks after sticking, rooted liners from cell pack, rose pot, and quart pot containers were transplanted into trade gallon containers. Thirty weeks after sticking, Nellie R. Stevens holly had a greater total root dry weight compared to Dwarf Burford holly. There were no differences in total root dry weight for any transplant treatment, but root distribution was influenced. Cell pack and rose pot liners transplanted twenty weeks after sticking showed a reduction in root growth in the root sector between the radius of a quart pot and a trade gallon pot. Shoot growth was also reduced for cell pack and rose pot liners that were transplanted into trade gallon containers twenty weeks after sticking.
Thomas G. Ranney and John M. Ruter
Temperature sensitivity of CO2 assimilation (ACO2), dark respiration, and chlorophyll fluorescence was evaluated among three taxa of hollies including I. aquifolium L., I. cornuta Lindl. & Paxt., and I. rugosa Friedr. Schmidt. Variations in foliar heat tolerance among these species were manifested in temperature responses for ACO2. Temperature optima of ACO2 for I. rugosa, I. cornuta, and I. aquifolium were 22.0, 26.3, and 27.9 °C, respectively (LSD0.05 = 2.9). Temperature responses of respiration were similar among taxa and did not appear to be contributing factors to variations in ACO2. At 40 °C, potential photosynthetic capacity, measured under saturating CO2, was 4.1, 9.4, and 14.8 μmol·m-2·s-1 for I. rugosa, I. aquifolium, and I. cornuta, respectively (LSD0.05 = 5.1). Variations in the relative dark-acclimated fluorescence temperature curves were used to assess thresholds for irreversible heat injury. The critical fluorescence temperature threshold (TC) was similar (48.0 °C) for all taxa. The fluorescence temperature peaks (TP) were 52.0, 52.8, and 53.5 °C for I. rugosa, I. cornuta, and I. aquifolium, respectively (LSD0.05 = 0.9). Based on these results, I. rugosa was the most heat-sensitive species, followed by I. aquifolium and I. cornuta. Ilex cornuta also had substantially greater potential photosynthetic capacity than the other species at 40 °C, indicating superior metabolic tolerance to high temperatures.
Edward F. Gilman, Thomas H. Yeager, and Diane Weigle
Dwarf burford holly (Ilex cornuta `Burfordii Nana') fertilized with N at 22.1 g per container yearly during production in the nursery generated more new shoot weight but less root weight after transplanting to a landscape than those receiving N at 14.8 g per container yearly. Slicing the root ball at planting, compared to not slicing, resulted in comparable regenerated root weight but reduced new shoot number, new shoot dry weight, and new shoot:regenerated root dry-weight ratio when irrigation was not applied daily after transplanting. Although irrigation frequency did not impact total weight of regenerated roots into landscape soil, more roots grew from the bottom half of the root ball when plants were irrigated periodically after planting than when plants received daily irrigation. Plants irrigated other than daily produced fewer shoots and less shoot weight than those receiving irrigation daily after transplanting. When plants were without irrigation for 4 or 6 days in the first week after transplanting, those planted without the nursery container on the root ball were more stressed (more negative xylem potential) than those planted with the container still on the root ball. However, 2 weeks later, plants without the nursery container were less stressed due to root growth into landscape soil.
Torin O. Pope and Caula A. Beyl
The Aquifoliaceae and Magnoliaceae families play an important role in seasonal holiday arrangements. For florists, floral designers, and seasonal gift shop owners, there is a great need to find cut foliage species suitable for use in floral displays. Foliage cuttings that retain their appearance, stay green, and do not drop leaves or berries are desired characteristics for greenery used in these displays. Because of their attractive foliage, the following species were chosen: Ilex × attenuata, Ilex vomitoria, Ilex cornuta `Rotunda', Ilex cornuta `Burfordii', Ilex opaca, Osmanthus heterophyllus, Ilex latifolia, and Magnolia grandiflora. For each species, cuttings were taken, fresh weights for these cuttings were obtained, and chlorophyll levels were measured. Measurements forweight and chlorophyll levels were then taken once a day for 5 days. After the five daily measurements, the measurements were taken once a week for 3 weeks. Based upon slow rate of water lost, chlorophyll retention, and visual rating of appearance, the two most suitable species were Osmanthus heterophyllus and Ilex latifolia. The Ilex vomitoria was unsuitable because of the tendency to drop leaves. The Ilex opaca was also unsuitable because of leaf drop and unattractive leaf curling.
Tim R. Pannkuk
Landscape water conservation methods and techniques contribute to managing water resources. Use of reference evapotranspiration (ETo) data and landscape coefficients is one method that needs further development. Local ETo data and actual plant water use were used to calculate plant factors (PFs) for three model landscapes composed of mixtures of turfgrass and shrubs. Model landscapes using a sandy loam soil included st. augustinegrass (Stenotaphrum secundatum), privet (Ligustrum japonicum), dwarf burford holly (Ilex cornuta ‘Burfordii Nana’), and dwarf yaupon holly (Ilex vomitoria ‘Nana’) at three ratios of turfgrass to shrub vegetative cover: 80:20, 50:50, and 20:80. Soil was placed into inground lysimeters in a complete randomized block design with soil moisture sensors and a drainage system. Lysimeters were irrigated with a sprinkler system, and water was applied at a rate of 100% replacement of ETo minus precipitation. Lysimeter soil leachate was collected from the drainage system and quantified. After 2 years, the PF of 20:80 and 50:50 turfgrass/shrub combination were greater than the PF of the 80:20 combination. Plant factors for the 80:20, 50:50, and 20:80 turfgrass:shrub combinations were 0.68, 0.97, and 1.01, respectively. There were no seasonal differences in PFs. Total growing season leachate depth over 2 years was 63.4, 30.7, and 12.6 mm for 80:20, 50:50, and 20:80, respectively. Further work on PFs should include other plant combinations, and evaluation in other climatic zones.
A.L. Shober, K.A. Moore, C. Wiese, S.M. Scheiber, E.F. Gilman, and M. Paz
response to irrigation compared with no irrigation ( Scheiber et al., 2008 ). Previous research conducted at the University of Florida suggested that burford holly ( Ilex cornuta ‘Burfordii Nana’), pittosporum ( Pittosporum tobira ‘Variegata’) ( Wiese et
S.M. Scheiber, E.F. Gilman, M. Paz, and K.A. Moore
Ilex cornuta ‘Burfordii Nana’, Pittosporum tobira ‘Variegata’, and Viburnum odorotissimum and 2) quantify the time until establishment. Materials and Methods Ilex cornuta ‘Burfordii Nana’, Pittosporum tobira ‘Variegata’, and Viburnum
Eugene K. Blythe and Jeff L. Sibley
1987 The reference manual of woody plant propagation: From seed to tissue culture Varsity Press Athens, GA Galle, F.C. 1997 Hollies: The genus Ilex Timber Press Portland, OR Gilman, E.F. 1999 Ilex cornuta ‘Burfordii Nana’ Univ. Florida Coop. Ext. Serv