Xtremehorticulture

Landscapes Have Too Many Plants and they are Big!

Use Fewer Plants Using fewer plants makes the remaining plants more visually important and saves water. A landscape full of plants is enamoring. It’s a jungle of plants. The temptation in our Western Hemisphere to fill “voids,” open spaces, with plants. Western floral arrangements are full of plants. However, each plant uses water. If we cluster them together, they are easier to water, easier to manage, and collectively use less. However, the more area not covered by plants, the lower a landscapes’ water bill. Western floral design fills all the spaces with flowers. We treat our landscapes the same way. Small Plants Use smaller plants. Smaller plants do the same job as larger plants and use less water. A decrease in plant size decreases their need for water. This leads to less total landscape water demand. If you already have large trees and shrubs, prune them smaller. Making plants smaller decreases their need for water. Remember, decreasing plant numbers and size only works if the amount of water they are given is also decreased. Manage the water they get. Eastern floral design stresses using negative spaces in interesting ways. Xeric Plants Use Less Water Use xeric plants. Xeric plants are watered less often, but with the same amount of water. Plants watered less often but still look good leads to a decrease in total landscape water use during the year. To do that, these plants need to be on a separate valve or station. Place xeric plants on separate valves or “water lines” (hydrozone) from plants that need water more often. Anytime plants are watered less often, even if you give a plant the same amount of water, a landscape saves water. Palo Verde is xeric in its water use because it comes from the Sonoran Desert Water Use is Set When it is Designed Once landscapes are designed and installed, future landscape water use, and how often they need water, is carved in stone. Watering plants less often does not always lead to better looking landscapes. Some plants, like mesic plants, need water more often. Plants demand for water is not negotiable. Once a landscape design has been selected, the landscape water use is set. When plants are watered less, changes in appearance occur; growth slows, leaves or needles begin to scorch and the canopy thins, leaves or needles drop, branches die, and finally the plant or tree may die. Use this as a signal to water more often. But water deep. When water is returned, many plants spring back to life. There is a tradeoff in perceived beauty vs. water use. Landscapes do not just have to be for plants. Conserving water is a reason homeowners are encouraged to use art forms in their landscapes that do not need water. Homeowners can become familiar with creating beautiful negative spaces without the use of plants. Our job in the desert is to create landscapes that conserve water while enjoying it at the same time. 

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Windbreaks and Screens in Desert Landscapes

Q. I was hoping to put up nice strong wind and sun block on the west and south west corner of our front yard, approximately 20 feet each way.  Could you give us some suggestions? I’ve talked to the neighbor on that side and we were thinking probably some kind of large bush. A. Windbreaks and screens for sunlight in the desert are usually best if they are close to the affected area. The reason is that plants used for screening or deflecting wind have to be pretty big to do any good when they are far away. Windbreak diagram but I cant remember where I got this from on the internet. sorry.             Larger plants require more water. If you put a windbreak close to the area where wind is a problem, then you can use smaller windbreaks and smaller plants and achieve the same thing. If wind or sun is a problem all year long then you would select evergreen plants.             If this problem is seasonal, you would select deciduous plants that drop their leaves in the fall and allow wind or sun through during winter months. Bill Stillman pomegranate windbreak in Bullhead City, AZ             General rule of thumb is that wind is affected on the downwind side of a windbreak from 5 to 8 times its height, depending on the type and direction of winds.             To be effective, windbreaks made from plants should be at least two layers thick and not a single layer or a few plants planted in a straight line. The majority of wind will be diverted over the top, bottom and around the sides of windbreaks. Wind that does go through a porous windbreak will be slowed.             How much it is slowed depends on how “porous” the windbreak is. Try to achieve about 20% porosity. In other words, about 20% of the windbreak has holes or pores in it. This lets wind through it, slows it and decreases the amount diverted up or around a windbreak. Fact Sheet on Establishing a Windbreak in the Desert             In the desert, think about structures to do this more than plants. These structures would be things like walls or trellises that can be covered with vines rather than large plants. A vine covering a wall or trellis will use far less water than plants the size and density needed to reduce wind speed and sunlight. Great way to add screen and windbreak in a desert landscape             Also, using a structure and vines or small shrubs in combination will achieve a more permanent solution to the problems and occupy less space in small residential landscapes. Avoid wood structures which crack and check in our dry heat. Instead use cement and metal options that are more resistant to our harsh environment.

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