Water Conservation

Plant Selections for Double Duty

When selecting plants for our yards we first consider what is beautiful. What other considerations make one plant preferable to another?

Will the plant fit?

Check plant size at maturity. Will there be room for roots that extend twice as far from the trunk as the longest branches? If not, pick a smaller variety.

Many homes have setbacks of less than 20 feet from block walls and streets; therefore, trees with 40-foot mature canopy widths are way too big for such an area. A canopy of 12 feet may fill a good-sized side yard.

Keeping a large tree small enough for a tight fit will require repeated pruning. Pruning wounds plants. Plants respond by directing resources to heal the wound. They use extra water to make food to heal every time they are wounded.

APS provides information on how to pick the right size tree.

Will the plant help reduce energy costs?

Temperatures under a tree can be as much as 25 degrees lower than those outside its shade. The surrounding air is cooled as much as 9 degrees compared to nearby pavement.

The water needed to keep a 200-square-foot lawn green could support a tree with a 15-50 foot canopy

Planting full-canopied, slow-growing trees rather than tall, skinny varieties on the west side of your home will make best use of their shade in blocking searing afternoon rays. The natural forms of mesquites, palo verdes, and mallees provide this screening.

Vines on a trellis will begin shading walls the year they are planted. Even six- to eight- foot trees can shade a window the first year they are planted.

Planting a tree or large shrub that shades your air conditioner without cutting off cooling air flow can cut your bill by 10%.

Will the plant affect other plants in the area?

Segregate plants by water demand

Planting desert trees within lawn areas results in over-watering the trees. Unnaturally fast growth can form weak wood. With shallow root systems encouraged by short watering cycles for the grass, the trees may become unstable in high winds and blow down.

Plant for light requirements

Tender young succulents will benefit from light shade provided by the open canopies of mesquite and ironwood trees in the desert. You won't see desert annuals like California poppies and lupine blooming in shade. Give them plenty of sunshine.

Plant for best shade purposes

A California study documented savings of $25 per month (185 kwh per season) when trees were planted on the west or south sides of home, which get the most sunlight. There was no benefit from planting on the east or north sides.

Will the plant affect security or access for maintenance?

Sharp agave leaves can be double-edged swords when placed near your home. In some cases they can provide security because their spiky leaves may discourage close approach by intruders. This is an advantage when they are placed under windows that you might want to keep open to provide night-time breezes. However, the agave or other thorny plants may present problems if plants are close to air conditioning units and outdoor faucets that you might need to get to.