Revised; Originally Published: 1983 / 2 pp. / An ideal hedge for screening patio areas should have dense foliage from the base to the very top of the plants. In order to develop a hedge with these qualities, the gardener should prune the plants in such a manner as to encourage the plants to develop branches and leaves at the lower portion at the time of planting and until the desired height is reached. The procedures for pruning shrubs are simple, but in many instances the basic principles are overlooked or not put into practice simply because the gardener does not want to sacrifice the growth of the plants before they reach the desired height.

Revised; Originally Published: 1983 / 2 pp. / Evergreen shrubs used to landscape the home grounds should be permitted to grow and develop into their natural shapes. Natural growing shrubs lend a pleasing look to the home grounds. This does not mean that we cannot prune to keep them within limited bounds, but we should definitely not prune to formal shapes such as globes, squares or pyramids. If they are pruned in this manner, they must be constantly sheared to maintain these shapes.

No description available.

No description available.

The objective of this project was to test the hypothesis that micritic, microbial, dendritic shrub structures transition into aragonite botryoids by serving as an organic substrate that promotes the initiation of aragonite crystal precipitation. Samples for this study were taken from three sources: 1) a stalactite found in the Lighthouse Reef Blue Hole, Belize; 2) aragonite botryoids in the reef framework of the Permian Capitan Formation and 3) the Lower Permian Laborcita Formation found in the Sacramento Mountains, south-central New Mexico. Samples studied in thin section and with scanning electron microscopy (SEM) showed dendritic micrite within botryoids and spheroidal shapes associated with aragonite. Precipitation experiments were conducted to grow calcite crystals with organic molecules in solution. The textures formed were very similar to those found at the three sample sites. Despite the similarity, all evidence of an organic substrate promoting precipitation remains circumstantial and therefore inconclusive.

A great number of trees and shrubs are at the disposal of the landscape gardener. He has at his command all kinds and types of plants, and by proper selections he can obtain any desired effect. Our native flora, which is rich in variety of material, has been supplemented to a great extent by the additional of many new things of great value. These new things have come from two sources, the hybridizer and from other countries. The hybridizer has given us new horticultural species and numberless new varieties; but the largest increase has come through the introduction of the native flora of other countries.

Vegetation reclamation in oil-sands requires a consistent and adequate supply of seeds of native shrubs. However, annual seed production is erratic and seeds are usually short lived and insufficient for the reclamation projects. Seeds of six native shrub species including: Prunus virginiana, Prunus pensylvanica, Arctostaphylos uva-ursi, Shepherdia canadensis, Cornus sericea, and Viburnum edule were used to analyze physiological changes during storage and artificial aging processes. The shrub seeds were studied for one year during storage under eight different combinations of temperature (-20, 4, 22.5 °C), atmosphere (Air / N2) and relative humidity (RH; 7-8 % / 3-4 %). No significant differences were detected among the storage parameters after one year; however, sub-zero and N2 environments showed a potential in maintaining a higher seed vigour during storage. In the artificial aging experiment, seeds were subjected to 45 oC, 60 % RH for 5-25 d. For most shrub species, the seed viability decreased significantly after 10-15 d artificial aging and was down to 0 % after 20 d. The germination percentage declined already after 5 d; therefore, there was a delay in detecting viability loss using the tetrazolium test. Non-aged seeds and aged seeds of most collections showed significantly different seedling lengths, which indicated a negative effect of accelerated aging process on the seedling growth. The electrolyte conductivity, as well as seed dehydrin protein expression, is strongly correlated with the seed vigour, which can be used as seed quality assessment methods in seed longevity predicting. A loss of membrane integrity occurred during the accelerated seed aging processes, as indicated by an increased electrolyte conductivity that was negatively correlated with the seed viability and germination. During artificial aging process, heat stress of Prunus virginiana induced expression of dehydrins with a molecular mass of 27 kDa, which reached a detectable level after 5 d. The storage protocol developed in this study would benefit the adequate supply of viable shrub seeds for reclamation. With species-specific parameters taken into consideration, the artificial aging technique to predict seed longevity can be further expanded to other non-crop species used in reclamation of lands after oil extraction.

10 pp. / Pruning recommendations for shrubs commonly planted in the low and mid-elevation desert in Arizona are given based on the intended use and individual plant growth characteristics.

The response of grass, forb, and shrub seeds to the subalpine environment during the fall and under winter snow and under laboratory conditions at 20/28 C was observed for 3 consecutive years at an elevation of about 3000m on the Wasatch Plateau in central Utah. Seeds in nylon sleeves were planted under 2 cm of soil before snowfall. Under snow plantings were made directly on the soil surface and under 2 cm of soil. The seeds planted before snowfall were removed each year on four occasions: when under snow plantings were made, after snow depth exceeded 130 cm (deep snow), just before spring snowmelt, and 10 or more days following snowmelt when soils had warmed. Seeds planted under snow or under snow and soil were removed on two occasions: after snow depth exceeded 130 cm and just before the snow melted in the spring. Environmental conditions which produced seed germination varied with species, origin of species, age of seed, and temperature. Fifty-four of the 60 species planted in September under 2 cm of soil before snowfall had some seed germinated when examined just before the snow melted in the spring. Fifty of the same species planted after winter snow covered the ground in November also had some seed germination just before the snow melted in the spring. Seed germination at the near 0 C temperatures on the soil surface under snow was usually similar to the comparable seed lots also placed under 2 cm of soil. Germinability of the grasses, forbs, and shrubs studied was placed in three broad classifications: (1) Little or no seed dormancy with germination at low and warm temperatures. Seeds germinated soon after harvest at temperatures near 0 C and also in the laboratory at 20/28 C. Examples are Agropyron desertorum, A. intermedium, Chrysothamnus viscidiflorus, and Lupinus alpestris. (2) Little or no seed dormancy with germination only at warm temperatures. Seeds did not germinate at the low temperatures present in the subalpine zone during the fall and winter but germinated readily in the laboratory at 20/28 C. Examples are Aquilegia caerulea , Potentilla gracilis var. pulcherrima, Rudbeckia occidentalis, and Valeriana edulis. (3) Dormancy at seed harvest. Germination was usually increased by near 0 C temperatures, by aging, and by other environmental conditions present under deep snow. Examples are Agropyron trachycaulum, Delphinium barbeyi, Madia glomerata, and Ribes cereum var. inebrians.

Fire suppression in the southern and central Appalachian Mountains has resulted in an alteration to vegetation structure and composition. For this research the dominant species, abundance, density and age structure of the ericaceous shrub layer is characterized on four sites across the southern and central Appalachian Mountains. Fire histories for each of the sites varied, and were determined in previous research using dendroecological techniques. Over 800 ericaceous shrubs were collected, species included Pieris floribunda (Pursh) Bentham & Hooker f., Rhododendron maximum L. and Kalmia latifolia L.. Basal area of ericaceous shrubs was significantly different between sites. Age structures show that when fire suppression started Ericaceae began to establish. A few Ericaceae cross-sections displayed scars, that are likely associated with fire events, suggesting they probably survived mild fire events. Ericaceous shrub age structures were also compared to SPB outbreaks and PDSI. There were no significant correlations, but field observations suggest that SPB may be providing conditions suitable for Ericaceae establishment. Topographic patterns reveal that Kalmia latifolia is most abundant at mid-slope positions and decreases at higher and lower slope positions. There were significant differences in the density between slope positions averaged across all sites. Sites with the most recent and frequent fires did not have any of the three ericaceous shrubs collected at the slope bottom or ridge-top. At the most fire-suppressed site Ericaceae are present at every slope position. Age structures reveal that the oldest Ericaceae are found at the mid-slope positions while the age of thickets appears to decrease away from the mid-slope position. This pattern suggests that Ericaceae are moving into slope positions where they were previously less abundant. Sites with the most recent frequent fire regime seem to have prevented Ericaceae from heavily inhabiting high and low topographic positions while also reducing the overall basal area and density of Ericaceae.