Chemical analysis was used to determine the concentrations of 12 nutrients in youngest fully expanded leaves (YFEL) of Leucadendron cvv. Silvan Red and Safari Sunset at 2 sites in the Mount Lofty Ranges. Leaves were sampled every month for 3 years, commencing in July 1990. The leaf nutrient data were used to define seasonal nutrient trends, thereby identifying the most suitable time for leaf analysis; to determine the magnitude of the differences in leaf nutrient composition between Leucadendron cultivars, and between Leucadendron and Protea hybrids; to calculate total nutrient removal by harvested stems, which can be used to formulate maintenance fertiliser programs; and to determine the correlations between nutrients. The seasonal increase in concentrations of nitrogen (N), phosphorus (P), potassium (K), and sodium (Na) in YFEL corresponded with the spring growth flush, after which concentrations decreased with time, particularly during summer and autumn. Concentrations of copper (Cu) and zinc (Zn) were unstable during October-April and the seasonal trends were not consistent between sites or with other mobile nutrients (e.g. N, P, K). Concentrations of calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), sulfur (S), and boron (B) at site 1 decreased early in the season, were lowest when vegetative flushing peaked, and tended to increase during autumn and winter. Seasonal variation in the main nutrients removed in marketable stems (i.e. N, Ca, K, Mg) was minimal during June-August. However, to assess the overall nutrient status of plantings, sampling in June is most suitable. Crop nutrient surveys conducted at this time, in conjunction with productivity and quality data, can be used to develop interpretation standards for leaf analysis. For all nutrients, the seasonal trends were similar for the 2 cultivars, but concentrations of Mn were consistently lower in YFEL of Silvan Red than Safari Sunset. In contrast to the small differences between cultivars, there were large differences in leaf nutrient composition between the Leucadendron cultivars and Protea 'Pink Ice'. For example, Mg, Na, and Mn concentrations were consistently lower, and N, K, Ca, and Fe higher, in YFEL of Pink Ice than in the Leucadendron cultivars. For these nutrients, different interpretation standards may be required for Leucadendron and Protea hybrids. The major nutrients removed in harvested stems were Na, N, Ca, K, and Mg. Based on nutrient uptake data alone, we suggest annual applications of N and Ca at 20-30 g/plant, and Mg and K at 10-15 g/plant, on acid sands. Significant (P<0.05) correlations were found between many nutrients. For example, N concentrations were positively correlated with P, K, Na, and Zn, and negatively correlated with Ca, Mg, and Fe concentrations. These significant relationships may indicate synergistic and antagonistic interactions between nutrients, which need to be considered when interpreting plant test data.

Seasonal fluctuations in the concentrations of 12 nutrients were assessed over 3 years for Protea 'Pink Ice' in 3 plantings in the Mount Lofty Ranges of South Australia. Nutrient concentrations in youngest fully expanded leaves (YFEL) generally showed strong seasonal trends, reflecting seasonal vegetative and flowering patterns. During May-August and December-February, YFEL concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), sodium (Na), sulfur (S), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) were relatively stable, making these suitable times for sampling. The effects of sampling error and leaf position were also determined. The error associated with our sampling procedure was within acceptable limits (coefficients of variation 45%) for N, P, K, Ca, magnesium (Mg), Na, S, and boron (B). Differences in nutrient composition between YFEL and YFEL - 1, YFEL - 2, YFEL + 1, YFEL + 2, and YFEL + 3 were of little practical significance. Nutrient removal by flowering stems and concentrations of nutrients in different fractions (bloom, stem + leaves, axillary shoots) of flowering stems were determined for each site. Nutrient concentrations in flowering stems were generally lower than in leaves. Nitrogen concentrations in axillary shoots and K concentrations in blooms were significantly higher than in other fractions. For preferred sampling times, seasonal trends showed that concentrations of N, P, K, Ca, Na, S, Cu, and Fe were fairly stable over May-August. Similarly, concentrations of N, P, K, Ca, S, Zn, and Mn were relatively stable during December-February, after completion of the spring vegetative flush.

The effects of nitrogen (N) and potassium (K) on stem growth and yield responses of Australian waxflowers were investigated. Experiments were conducted in commercial plantings at 3 sites in South Australia. Plantings of Chamelaucium uncinatum cvv. Alba (2 sites) and Purple Pride (1 site) and a Chamelaucium hybrid (C. floriferum x C. uncinatum), known locally as Walpole wax (1 site), were 3-5 years old when the study began in 1990. Nitrogen and K were applied at rates up to 160 g N and 80 g K/plant.year. Application of N significantly (P<0.05) increased stem growth, with the magnitude varying considerably between sites and years. Increasing the rate of applied N from 0 to 80 or 160 g/plant.year increased mean tip-growth of flowering stems of cv. Alba by 47.7% at site 1 and 137.1% at site 3, and of Walpole wax by 144.2% at site 2. In contrast, the effect on cv. Purple Pride was minimal. Tip-growth also varied significantly (P<0.05) between sites. Applied K did not significantly affect stem growth at any site. Application of N significantly (P<0.05) increased the yield of 41-70 and >70 cm stems, and total stem yield at all sites with variation between years and cultivars. For example at site 2 increasing the applied N rate from 0 to 80 or 160 g/plant .year increased total stem yield by 13.9, 176.2 and 77.6% in 1991, 1992 and 1993, respectively. In contrast, the effect of applying K was inconsistent. Application of N significantly increased the weight of prunings at all sites and yield of prunings also varied between years. Applied K significantly affected the yield of prunings at site 3, where application of 80 compared with 0 g1plant.year decreased the yield by 17.9%. For all sites, the mean ratios between total stem weight and total biomass harvested were in the range 0.68-0.82. The effect of applied N was only significant at site 3, where the ratio decreased from 0.76 to 0.57 when the rate of applied N increased from 0 to 160 g/plant.year. The effect of K was not significant at any site. At sites 1 and 2, and for cv. Alba at site 3, application of 80 or 160 g N1plant.year decreased mean stem dry matter by 8.0, 9.3 and 11.0%, respectively. Stem dry matter content also varied significantly between years at all sites. The effect of applied K was only significant at site 3, where application of 80 g1plant.year reduced dry matter content by 5.3% compared with 34.2% for the nil rate. Based on data for all sites, stem fractionation showed that dry matter yields (as a percentage of total stem dry weight), were in the order, woody tissue (3 15-49.9%) > leaves (22.1-29.2%) > flowers (15.9-25.8%) > tip-growth (5.0-21.9%). The effect of applied K on the yield of the different stem parts was only significant (P<0.05) at site 1, where in 1991 yield of the tip-growth fraction decreased. We conclude that to develop effective N fertiliser strategies for waxflowers requires knowledge of (i) soil type, in particular residual N fertility; (ii) annual vegetative growth cycle (i.e. periods of growth flushing); (iii) harvest period; and (iv) flowering time. For cultivars or hybrids harvested when vegetative growth is negligible (e.g. winter) N nutrition can be optimised, while for those harvested during periods of vegetative flushing (e.g. September-November) lower rates of N should be applied to ensure tip-growth is not excessive. Although yield responses to applied K were inconsistent, we recommend 20 g K/plant.year to ensure that productivity is maintained over the 5-10 years flowering stems can be harvested from commercial plantings.

Seasonal fluctuations in the concentrations of 12 nutrients were assessed over 3 years for Chamelaucium uncinatum cultivars Alba and Purple Pride and for Chamelaucium hybrid (C. floriferum  C. uncinatum) known locally as Walpole wax. The plantings were located in the Mount Lofty Ranges, Lower South East and Lower Murray regions of South Australia. Tips of stems, 25-40 mm long, were collected on a monthly basis. The nutrient data were used to identify the most suitable time for tissue analysis; to determine the magnitude of the differences in nutrient composition between cultivars; and to determine the correlations between nutrients. The effect of the sampling error was also determined. The seasonal decrease in concentrations of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and sulfur (S) corresponded with vegetative flushing (growth dilution effect). Concentrations of the variably mobile nutrients copper (Cu) and zinc (Zn) were unstable, particularly 1873 during autumn-winter. Concentrations of phloem immobile nutrients calcium (Ca), boron (B), and manganese (Mn) decreased early in the season, were lowest when vegetative flushing peaked (summer), and tended to increase in autumn and winter. For preferred sampling times, seasonal trends showed that concentrations of N, P, Ca, Mg, sodium (Na), chloride (Cl), B, Zn, and Mn were fairly stable over the period JanuaryMarch. Similarly, concentrations of K, S, and Cu were relatively stable during the period July-September when vegetative growth was minimal. The error associated with our sampling procedure was within acceptable limits (coefficients of variation <10%) for N, P, K, Ca, Mg, Na, Cl, S, B, and Mn. For the cultivar Alba, the seasonal trends for all nutrients were similar even though they were grown at different sites. Nitrogen and Mg concentrations in stem tips of the cultivar Alba were consistently higher than those in stem tips of the cultivar Purple Pride. In contrast, concentrations of K, Na, Cl, and Mn were lower. For these nutrients, different interpretation standards may be required for these cultivars. Significant (P < 0.05) correlations were found between many nutrients. For example, K concentrations were positively correlated with Cl, S, Cu, and Zn and negatively correlated with Ca and Mg concentrations. These significant relationships may indicate synergistic and antagonistic interactions between nutrients, which need to be considered when interpreting plant test data.

The effects of nitrogen (N) and potassium (K) on leaf colour, vase life of flowering stems, and soil pH and electrical conductivity (conductance) were investigated for Australian waxflowers. Experiments were conducted on commercial plantings of Chamelaucium uncinatum cvv. Alba and Purple Pride, and a Chamelaucium hybrid (C. floriferum x C. uncinatum) known locally as Walpole wax, at 3 sites in South Australia. Nitrogen (as NH4NO3) and K (as K2SO4) were applied at rates up to 160 g N/plant and 80 g K/plant over several side dressings during the growing season. Application of N significantly (P<0.05) increased leaf colour ratings for the cv. Alba and Walpole wax. At the higher N rates leaves were dark green. Differences between years were small compared with the effect of applied N. The N x year interaction, and the effect of applied K, were not significant (P>0.05) at any site. For cv. Alba, application of N significantly increased vase life by 5 days in 1992 and 3 days in 1993. For Walpole wax, the effect of N was not consistent between years. Each year, the vase life of flowering stems from cv. Alba were consistently greater compared with stems from Walpole wax. Application of K did not significantly (P>0.05) effect vase life at any site. Annual applications of 80 or 160 g N/plant, as ammonium nitrate, significantly decreased soil pH by 0.3-1.4 units after 2-3 years, whereas application of K, as potassium sulfate, did not affect soil pH. The effect of applied N on soil conductance, although significant, was not consistent between sites. For example, at site 1, increasing the rate of applied N from 0 to 80 g N/plant increased conductance from 0.04 to 0.08 mS/cm in 1992. However, in 1993 it decreased from 0.04 to 0.02 mS/cm. The low conductance values (0.02-0.09 mS/cm) in the 0-60 cm soils, show that fertiliser salts did not accumulate over the course of the study to concentrations which adversely affect plant growth and yield. We conclude that N stress was a significant factor in the occurrence of poor leaf colour, and may be a major factor in the occurrence of defoliation during the flowering period. Optimising N nutrition improved leaf colour, vase life and, depending on the rate, did not significantly increase soil acidity or conductance after 2-3 years.