Exposure to sun and wind are important considerations in plant selection. Drying winds and reflected heat from buildings cause desiccation, especially during winter when the ground is frozen and moisture is unavailable to plants. Prolonged desiccation can result in death of individual cells and plant tissue. Some plants have defense responses to decrease the effects of desiccation. An example is the leaves of broad-leaf evergreens which curl to reduce the amount of leaf surface exposed to drying winds.
In summer, DROUGHT combined with high temperature and drying wind will cause noninfectious or environmental LEAF SCORCH on many plants. Leaf scorch can be intensified for trees that have roots growing under pavement. In this situation, moisture sources are blocked by the pavement. Additionally, as the pavement heats, it raises the temperature of the surrounding soil, causing the tree to lose more moisture.
The amount and intensity of sunlight influence plant growth and selection. Plants are often listed by sun and shade requirements. Placing a plant that requires a sunny exposure in a shaded environment may result in slow, leggy growth, reduced flowering, and poor fall color. Conversely, plants that naturally grow in shade are likely to show symptoms of desiccation and leaf scorch when placed in a sunny exposure.
There are various degrees of sun or shade. Full sun means six to eight hours of exposure to sunlight. Filtered shade is sun coming through a canopy of leaves. Partial shade refers to an area that is shaded for part of the day and sunny for less than six hours a day. Deep shade is cast from a structure resulting in little or no direct sunlight.
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Microclimates |
