Landscaping Services in Phoenix, AZ

Landscaping in Phoenix

Phoenix landscaping has two jobs: use very little water, and produce shade. A yard that does the first without the second is a gravel lot that nobody goes into from May to September.

Caliche and Desert Soil

Phoenix soils are alkaline, low in organic matter, and frequently underlain by caliche — a cemented layer of calcium carbonate that can sit anywhere from a few inches to several feet down and can be a few inches to several feet thick.

Why it matters: caliche is close to impermeable. A hole dug into or through partial caliche fills with water and does not drain. In a desert, plants die of drowning more often than most people expect, and this is why.

What to do:

• Percolation test every planting hole. Fill it with water. If it has not drained within a few hours, you have a drainage problem.
• Break through the caliche layer if it is thin, with a digging bar or an auger, so water can drain to permeable soil below.
• Plant high on a mound where breaking through is impractical.
• Do not backfill with rich compost. Amended soil in a caliche bathtub holds even more water. Backfill with native soil so roots are encouraged out of the hole.

Alkaline soil also locks up iron, causing chlorosis — yellow leaves with green veins — in plants not adapted to it. The answer is to choose adapted plants rather than to fight the pH.

Water and Irrigation

Drip is the only sensible choice. Spray irrigation in Phoenix loses an enormous fraction to evaporation before it reaches the soil, and it wets foliage that does not want to be wet.

Design principles that matter here:

• Emitters at the drip line, moved outward as the plant grows. Emitters left at the trunk for years produce a plant with no root spread that blows over in a monsoon.
• Deep and infrequent. Desert plants want a thorough soak that penetrates a foot or more, then a long dry period. Frequent shallow watering creates shallow roots and dependent plants.
• Seasonal schedule changes. A controller left on the summer schedule through winter is the most common source of an enormous Phoenix water bill, and it also kills plants through winter overwatering.
• Check emitters twice a year. They clog with the same mineral scale that affects everything else here.

A Palette That Works

Trees for shade — this is where the real value is:

• Desert Willow — fast, flowering, deciduous, well behaved.
• Palo Verde (Museum or Desert Museum hybrid) — the classic, thornless in the hybrid, brilliant spring bloom.
• Mesquite (Velvet or Honey, native species rather than imported Chilean) — deep-rooted, sturdier in monsoon wind.
• Ironwood — slow, extremely long-lived, evergreen.
• Pistache and Chinese Elm for more traditional canopy where more water is acceptable.

Avoid Eucalyptus and imported Chilean mesquite in monsoon country; both are prone to failure in high wind.

Shrubs and perennials — Texas Ranger, Brittlebush, Desert Marigold, Damianita, Autumn Sage, Red Yucca, Fairy Duster, Bougainvillea in frost-protected spots.

Succulents and cactus — Golden Barrel, Agave, Ocotillo, Prickly Pear, Saguaro. Note that saguaros are protected under Arizona native plant law and cannot simply be moved or removed.

Groundcover — Trailing Rosemary, Damianita, Dalea. Decomposed granite as mulch between.

Shade Is the Design Goal

A Phoenix yard without shade is unusable for a third of the year, and it makes the house more expensive to cool.

• Shade the west wall. Afternoon sun on a west elevation is the single largest heat gain on a Phoenix house. A tree there pays for itself in cooling costs.
• Shade the air conditioning condenser — but not so closely that airflow is restricted. Several feet of clearance with shade above improves efficiency.
• Consider ramadas and shade sails where a tree will take fifteen years. They work immediately.
• Avoid large expanses of bare gravel near the house. Gravel re-radiates heat into the evening and raises the temperature of the outdoor space substantially.

Timing

• October to March is the planting season for nearly everything. Autumn is best: warm soil, mild air, and a full winter to establish before summer.
• Spring for cactus and succulents, which want warm soil to root into.
• Never plant in May or June unless you are prepared to nurse the plant through its first summer with supplemental water.
• Prune in late winter for most desert trees, before spring growth. Avoid heavy summer pruning, which exposes bark to sunscald.

Costs in Phoenix

Monsoon and Wind

Summer microbursts topple trees, and the pattern is predictable: shallow-rooted trees that have been watered close to the trunk, and trees that have been over-thinned or topped.

• Move emitters outward as the tree grows, to encourage a wide root plate.
• Do not over-thin the canopy. A tree needs its foliage to move wind through it. Gutted canopies catch wind at the ends of long bare limbs and snap.
• Stake only when necessary and remove stakes within a year. Permanently staked trees never develop trunk strength.

Tips for Phoenix Homeowners

1. Percolation-test every planting hole. Caliche kills more Phoenix plants than drought does.
2. Plant in autumn. It is the single biggest factor in whether a plant survives.
3. Move drip emitters outward as plants grow, or you are raising a tree that will fall over.
4. Change the irrigation schedule seasonally. A summer schedule left running in January wastes water and drowns plants.
5. Design for shade on the west side. It is comfort and it is a lower cooling bill.