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  • Author or Editor: R. D. Wright x
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Abstract

Incorporation of superphosphate into a pine bark growing medium did not increase growth of ‘Hellen’ holly if the plants were subsequently fertilized with slow-release granular or a water soluble fertilizer. Tissue P levels, except for the water soluble fertilizer treatment, and medium P levels were higher as a result of superphosphate incorporation.

Open Access

Abstract

Ilex crenata ‘Helleri’ liners were greenhouse grown in sand culture and subjected to N rates which ranged from 14 to 108 ppm in one experiment and from 70 to 250 ppm in a second experiment. Maximum shoot dry weights occurred at 87 ppm N in the first experiment and at 100 ppm N in the second experiment. The number of plants per treatment initiating visible shoot elongation 17 days after the initiation of the fertilizer treatments was influenced by N treatment and 79% of the differences in final dry weights could be attributed to the time of visible shoot elongation initiation. The maintenance of 87–100 ppm N in the substrate nutrient solution, the range at which no further increase in shoot dry weight occurred, would maximize plant growth and most effectively utilize the applied fertilizer.

Open Access
Authors: and

Abstract

Higher N rates applied to Ilex crenata‘ Helleri’ holly liners grown in the greenhouse increased shoot growth but-decreased root growth resulting in a greater shoot:root ratio. Higher N rates reduced the time required for a shoot growth flush to occur. Ρ at 85-500 ppm had no effect on shoot or root growth. Continued growth of liners at 50 ppm N lowered the shoot:root ratio due to stimulation of root growth while 300 ppm N caused the shoot:root ratio to increase due to increased shoot growth.

Open Access
Authors: and

Abstract

Intemodal and stem lengths of new growth and plant diameter of dwarf Japanese holly (Ilex crenata Thunb. cv. Helleri) were significantly increased by sprays of 100, 200, or 400 ppm gibberellin A4+7 (GA4+7). GA3 was less effective than GA4+7, but also significantly increased stem length and plant diameter. Leaf size was decreased by GA3 and GA4+7 applications.

Open Access
Authors: and

Abstract

Greenhouse-grown branched liners of ‘Helleri’ holly were fertilized with either 0, 5, 10, 15, 20, 25, or 30 ppm P to establish a P level in the pine bark medium that resulted in maximum shoot dry weight. Pine bark P levels greater than 10 ppm did not result in increased shoot dry weight. Total mg of P in shoot tissues continued to increase with P treatments higher than 10 ppm, indicating luxury consumption of P. Total mg of P in root tissues increased to the 5 ppm P treatment. Total μg of Mn in shoot tissues increased while total pg of Mn in root tissues decreased with increasing pine bark P levels. In a subsequent experiment, dry shoot weights of ‘Helleri’ holly grown in a pine bark medium amended with either 270, 540, or 810 g/m3 of P supplied as superphosphate (9% P) or fertilized with 10 ppm P were not different, while root dry weights decreased with increasing P amendment. Water extractable P for the 810 g/m3 treatment decreased 245 ppm during the experiment and by week 5 was below 10 ppm.

Open Access
Authors: and

Abstract

Pine bark cation exchange capacity (CEC) (by Ba/Mg exchange on four particle size fractions) increased regularly from 38 to 98 meq/100 g between pH 4 and 7. Decreasing particle size from <2.38 to <0.05 mm did not result in the expected large increases in bark CEC. The Ba/Mg CEC of unsieved bark samples was less than that determined by the weighted average of component size fractions. Monovalent/monovalent-determined CEC was higher than Ba/Mg, indicating that a number of differing charge-specific sites are involved. The pH-dependent CEC increase between pH 4 and 7 was greater for divalent exchange than for monovalent. Ammonium/K CEC was higher than K/NH4 CEC, probably due to enhanced NH4 adsorption by carboxyl groups. Infrared analysis of pine bark revealed that surface functional group composition is similar to soil organic matter. The accurate measurement of CEC in pine bark is complicated by solution pH and ionic strength, as well as by the cations employed for exchange.

Open Access

Abstract

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.’

Open Access

Abstract

Most woody ornamentals purchased by Virginia retailers were ordered from states south of Virginia; 12% were purchased from West Coast growers. Of plants grown in Virginia, 43% were shipped to northeastern states and 46% were marketed within the state. Marketing plants in containers extended the traditional fall and spring marketing season of ball and burlapped plants. Most plant deliveries to retail outlets occurred from March to April and from August to September.

Open Access