The effects of 3 nitrogen levels and 2 growth regulators on growth of winter- and summer-rooted cuttings of Ilex crenata cv. Helleri were studied. Nitrogen applications promoted bud break immediately after rooting on summer cuttings and also enhanced the growth of winter-rooted cuttings. Generally, plants grown at 300 or 150 ppm N had greater shoot numbers and length, height, width, and dry weight compared to plants grown at 50 ppm N. Also spring growth of these liners was markedly enhanced by the higher level of N applied the previous season. Benzyladenine (BA) at 600 ppm increased the number of breaks and suppressed stem length, while gibberellic acid (GA3) at 400 ppm decreased the number of breaks and increased stem length.
Taxus media Rehd. ‘Anderson’ were grown at 4 boron rates: 0.5, 5.0, 25.0 and 50.0 ppm using 2 media:4 pinebark:l sand and 4 hardwood bark:l sand. toxicity symptoms developed when foliar concentration was between 85–100 μg/g of dry tissue. Foliar symptoms of toxicity were characterized by leaf-tip yellowing followed by leaf-tip necrosis and premature defoliation. Shoot and root growth were suppressed at the 50 ppm application rate. continued to accumulate in the foliage after the 2 higher rates of were discontinued. Foliar concentration of Ca, Mn, Fe and Zn were lower when plants were grown with 25 and 50 ppm when compared to plants grown with 0.5 and 5 ppm B.
Fertilizer applied during a period following the cessation of stem elongation and before the next flush resulted in greater total tissue N and shoot growth than applications made during other stages of growth in ‘Helleri’ holly. Root growth was suppressed by 3 or more fertilizer applications, regardless of the time of application.
The effects of 3 nitrogen treatments on tissue N fluctuations of ‘Helleri’ holly. All N concentrations increased following the cessation of shoot elongation until a concentration of tissue N was reached where a new flush of growth began. Nitrogen concentrations at which new growth began were about the same for all N treatments. The time necessary to reach this concentration was dependent on the level of N added; 5 weeks for 300 ppm, 13 weeks for 150 ppm and 18 weeks for 50 ppm N. Once new growth began, tissue N concentrations began to decrease.
High correlation coefficients were found between plant growth (dry weight accumulation) and both leaf N content and soil solution nitrates, while low correlation coefficients were found between soil nitrates and plant growth of 3 holly cultivars, Ilex crenata Thunb. cvs. Helleri and Rotundifolia and Ilex cornuta Lindl. et Paxt. cv. Burfordi, grown in 3 liter container at 200, 300, 400 and 500 ppm nitrogen. Shoot growth of ‘Helleri’ and ‘Burfordi’ was not increased by N levels higher than 300 ppm, while 400 ppm was optimal for ‘Rotundifolia.’
Two studies were conducted to evaluate recycled newspaper mulch for landscape plantings. In the first study, two paper products (pellets and crumble) were tested at three depths. Application of either 25 or 50 mm provided excellent control of prostrate spurge. Of the four annuals grown, ageratum exhibited severe stunting of roots and shoots. In the second study, three annual species were mulched with the two recycled paper products applied at 25 mm each and adjusted with P at 0, 3.75, or 7.5 ppm to bind excess Al. When no P was added, ageratum growth was about half that of the control plants. Addition of P at either rate resulted in similar growth compared to control plants. Marigold and geranium were less affected by recycled paper mulch; however, when P was added growth was always similar to nonmulched control plants.
Phytotoxicity associated with application of 0.28 kg·ha−1 a.i. of the 4E formulation of fluazifop-butyl to Rhododendron ‘Hino-crimson’ was characterized by plant response similar to the response to chemical pinching. Flowering the following spring increased with fluazifop-butyl treatment. In a separate study, application of 1E PP005 (a formulation containing only the active isomer fluazifop-butyl) produced effects similar to the 4E formulation at one-half the rate (0.14 kg·ha−1). Chemical name used: butyl (±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-butyl).
Improved water use efficiency exists for plants grown in modified containers to minimize leaching and reduce irrigation frequency which subsequently reduces NO3-N leachate. Salvia splendens `Bonfire' and Impatiens wallerana `Pink' (super elfin hybrid) were potted in ProMix BX medium (Premier Brands, Inc., Stamford, CT) into nine container styles with modified drainage holes to determine leachate volume and quantify NO3-N leached. Three styles had four drainage holes on the container side with hole diameters of 0.5, 1.0, and 1.9 cm, respectively; three styles had four drainage holes on the container side and one drainage hole in the bottom center with hole diameters of 0.5, 1.0, and 1.9 cm, respectively; and three styles had one drainage hole in the bottom center with hole diameters of 0.5, 1.6, and 1.9 cm, respectively. Plants were hand watered when an individual container's medium reached 80% of container capacity. Leachate volume, irrigation frequency, and leachate NO3-N was reduced as drainage size hole decreased in size and number. Plant quality was similar among container modifications.
Selected herbicides were evaluated for control of southern yellow wood sorrel (Oxalis dillenii Jacq.) in three experiments. Control varied depending on rate of application and the time interval after application. Herbicides providing excellent control (less than one weed/pot) 8 weeks after treatment with the 0.5 × rate included: oxyfluorfen, 1.1 kg·ha–1; oryzalin, 2.2 kg·ha–1; and oxyfluorfen + oryzalin, 1.7 kg·ha–1. Control 18 weeks after treatment was excellent at the 1× rate with oryzalin (4.5 kg·ha–1) and at the 2× rates with oryzalin (9.0 kg·ha–1), oxyfluorfen (4.5 kg·ha–1), and a combination of the two. Chemical names used: 2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin).
Fluctuations of macronutrient levels in the leaves, stems and roots were analyzed in Cotoneaster dammeri, C. K. Schneid, cv. Royal Beauty and Juniperus horizontalis, Moench cv. Piumosa during the overwintering period. Potassium, Mg and Ca levels, in both species, maintained periods of relative stability. Tissue P levels remained stable in all tissues, while Ν levels in leaves, stems and roots of both species fluctuated significantly throughout the sampling period.