Gardening Tips
Butterfly Garden
Hummingbird Garden
Wildflowers
Oracle Wildflowers Unlisted
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Trees: Landscape
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Oracle, Arizona

Ericameria laricifolia: Turpentine Brush in October

Gardening Tips

Selecting Plants for Oracle
  1. Choose plants that grow in our climate zone. For the uphill (south or mountain) side of Oracle, the USDA climate zone is 8b. For the downhill (north or desert) side of Oracle, the USDA climate zone is 9a. We have winter temperature minimums of 15-19°F uphill and 20-25°F downhill, spring drought April through June, July temperatures over 100°F, and monsoon rains in July and August.
    Because Oracle is mountainous, we have many micro-climes throughout the town that are hospitable to a variety of plants. We are officially Sunset Western Garden zone 10, but plants that are defined as suited to all three Sunset zones 8, 9 and 12 will also grow here when the micro-clime is suitable.
    The elevation above sea level for Oracle, Arizona, is 4500 feet. Other Arizona cities with the same or similar elevation are Sedona, Sierra Vista, and Tombstone.
  2. Avoid water-hungry plants. Our high desert region receives limited rain and we have endured many years of drought. Plants with low water needs require less maintenance.
  3. Select plants that prefer the pH 7.0 (neutral) to pH 7.5 (slightly alkaline) soil of our desert sky mountain. Acid-loving plants require heavy soil modification and periodic fertilizer. The water supply of Oracle is also alkaline, putting further stress on an acid-loving plant.
  4. Choose desert-compatible plants that our desperately hungry wild critters dislike. These drought-resistant plants are less tasty to wildlife and often grow back quickly when nibbled.

Digging Holes for Plants
  1. To dig a hole in the hard soil of the high desert, dig a circle several inches deep of the proper width, then pour in water. Wait until the water is absorbed, then dig out the mud and add more water. Repeat until the hole is the proper depth. Digging can also be performed after a heavy rain when the ground is soft.
  2. Fill the completed hole with water to check for drainage. If it does not drain, use a metal rod and hammer to pound holes through the bottom until drainage is attained. Or use a pickaxe to dig a chimney below the decomposing granite. Ensuring good drainage is the most important part of digging a hole. If you cannot get the hole to drain properly, fill it in and dig a hole in another spot.
  3. Oracle does not have caliche, but does have decomposing granite that is often mistaken for caliche. It is a variable brown / reddish-brown / white mixture. Thickness varies considerably. Digging requires a pickaxe, with lots of patience, or a jackhammer.
  4. In general, because of hard soils, dig the hole before you buy the plant. Do not buy more than one plant at a time without a hole already dug. This will prevent a plant from sitting around in a container with its roots getting baked by the sum.
  5. Holes should be one to two inches shallower than the root ball and FIVE times as wide. This allows roots an opportunity to grow before they run into rock-hard dirt. A wide hole also allows more rainwater to accumulate around the roots in our hot, dry climate and will reduce watering frequency.
  6. To plant groundcover on a slope, dig narrow trenches perpendicular to the direction of the slope. The trenches should be the width of a pickaxe and eight inches deep. A trench will collect and retain more water than a round hole. The species and variety of plant being grown will determine the distance between the trenches. Check for drainage, and if necessary, make a narrow cut from the center of the trench downslope to drain excess water.