10 Things for a Sustainable Landscape Design

https://www.houzz.com/magazine/10-things-to-consider-for-a-more-sustainable-landscape-design-stsetivw-vs~126874829/

One important part of sustainable landscaping:

is plant selection. Most of what makes a landscape unsustainable is the amount of inputs required to grow a non-native plant on it. What this means is that a local plant, which has adapted to local climate conditions will require less work on the part of some other agent to flourish. For example, it does not make sense to grow tomatoes in Arizona because there is not enough natural rainfall for them to survive without constant watering. Instead, drought-tolerant plants like succulents and cacti are better suited to survive. Also, by choosing native plants, one can avoid certain problems with insects and pests because these plants will also be adapted to deal with any local invader. The bottom line is that by choosing the right kind of local plants, a great deal of money can be saved on amendment costs, pest control and watering.

Plants used as windbreaks can save up to 30% on heating costs in winter. They also help with shading a residence or commercial building in summer, create cool air through evapo-transpiration and can cool hardscaped areas such as driveways and sidewalks.[35]

A house surrounded by local trees or bushes enjoys multiple benefits. Plants release water vapor in the air through transpiration and water has the ability to reduce temperature extremes in the areas near it (as it boasts very high heat capacity). The larger and more leafy the plant, the most water vapor it produces. Additionally, the presence of trees is crucial in the creation of stable, healthy and productive ecosystems (such as forests). In fact this is an important principle of permaculture.

If the surrounding trees are chosen to produce edible fruit they can provide a sustainable food source for the occupants of the house. Even if some are fairly demanding (especially in the summer), irrigation is an excellent end-use option in greywater recycling and rainwater harvesting systems, and a composting toilet can cover (at least) some of the nutrient requirements. Research suggests that diluted human urine might be as effective as chemical fertilizers.[citation needed] Not all fruit trees are suitable for grey-water irrigation, as reclaimed grey-water is typically of high pH and acidophile plants don’t do well in alkaline environments.

An intelligent choice

for direct energy conservation would be the placement of broad-leaf deciduous trees near the east, west and optionally north-facing walls of the house. Such selection provides shading in the summer while permitting large amounts of heat-carrying solar radiation to strike the house in the winter. The trees are to be placed as closely as possible to the house walls but no closer than 1 meter – otherwise the roots can cause substantial foundation damage. A sustainable house will most likely be equipped with south-facing (north-facing in the S. hemisphere) photovoltaic panels and a large, south-facing glazing as a result of passive solar heating design. As the efficiency of both systems is very sensitive to shading, experts suggest the complete absence of trees near the south side.

Another intelligent choice

would be that of a dense vegetative fence composed of evergreens (e.g. conifers) near that side from which cold continental winds blow (usually north in the N. hemisphere) and also that side from which the prevailing winds blow (west in temperate regions of both hemispheres). Since north winds are most cold and westerlies blow most often, such choice creates an effective winter wind-barrier that prevents very low temperatures outside the house and reduces air infiltration towards the inside. Calculations show that placing the windbrake at a distance twice the height of the trees can reduce the wind velocity by 75%. It then follows that, with some planning, both arrangements (deciduous and evergreen) can be applied simultaneously.[36]

The above vegetative arrangements

come with two disadvantages. Firstly, they minimize air circulation in summer (although in many climates heating is more important and costly than cooling) and, secondly, they may affect the efficiency of photo-voltaic panels, thus prompting the need for a shading analysis. However, it has been estimated that if both arrangements are applied properly, they can reduce the overall house energy usage by up to 22%