Recommended Plants for Sierra Vista
This low water landscaping plant list contains native and desert adapted plants that are, with a few exceptions, hardy to at least 15 degrees F. The exceptions are indicated as marginal. Cochise County is designated as Hardiness Zone 8 by the United States Department of Agriculture (USDA), and Zone 10 in the Sunset Western Garden Book. If properly planted and maintained, the recommended plants should provide an easy care, water efficient, and attractive property.
Not all plants on this list are available at local nurseries and outlets; however, landscapers and nurseries have access to growers and wholesale distributors with larger inventories. Many nurseries and outlets will gladly special-order plants not in stock. Avoid purchasing plants that are not hardy to at least 15 degrees F and that require regular or ample irrigation.
Remember, by landscaping with plants that are not native or desert adapted, you will invite trouble and will be wasting your money, time, and our most precious resource: water.
Watering intervals
Watering too little can cause plants to wilt and die, but too much water starves the roots of oxygen and encourages weed growth. Irrigation intervals are different for newly planted plants, established plants, and types of plants (trees, shrubs, perennials, etc.). The intervals suggested below were developed for the Phoenix area and can be used as a guide for Cochise County. Water according to this schedule and adjust as necessary.
Watering intervals for newly planted desert-adapted plants
It usually takes one years to establish small plants, two years for shrubs, and three years for trees.
| Week | Summer | Fall through spring |
|---|---|---|
| 1-2 | Every 1-2 days | Every 3-4 days |
| 3-4 | Every 3-4 days | Every 6-7 days |
| 5-6 | Every 4-6 days | Every 7-10 days |
| 7-8 | Every 7 days | Every 10-14 days |
| After week 8 | Gradually extend the time between irrigations until plants are established. | Gradually extend the time between irrigations until plants are established. |
Watering intervals for established desert-adapted plants
Once established, many native and desert adapted plants can survive on rainfall along with occasional supplemental watering during extended dry periods. Even during dry periods, established succulents need very little water, so do not water them unless you see signs of stress.
If you water more frequently for shorter periods of time, you may be encouraging shallow root growth, inviting failure, and wasting water.
| Week | Spring | Summer | Fall | Winter |
|---|---|---|---|---|
| Trees | 14-30 days | 7-21 days | 14-30 days | 30-60 days |
| Shrubs | 14-30 days | 7-21 days | 14-30 days | 30-45 days |
| Perennials | 14-30 days | 7-21 days | 14-30 days | 21-45 days |
| Succulents | 21-45 days | 14-30 days | 21-45 days | If needed (see instructions below) |
Watering intervals for non-desert adapted plants are much more frequent and result in a waste of our precious water. When you water make sure you water at the drip line to the depth of the root zone (1 foot deep for annuals, biennials, perennials, and groundcovers, 2 feet deep for shrubs, and 3 feet deep for trees each time you water). After one hour, a good way to test moisture depth is to insert a metal rod into the irrigated area. If the rod pushes down easily to the required depth, then the soil is sufficiently irrigated. Water again when you can't push the rod more than four inches into the ground. If you encounter resistance when you try to push the probe into the soil, then you have not watered deeply enough. If you don't encounter resistance at the prescribed depth, then you probably have over-watered. Water again when you can't push the rod more than four inches into the ground. Deep and infrequent watering is a good practice to follow as it makes your plants more water efficient.
Because of differing water needs, it is best to place trees and shrubs on separate irrigation valves. If the irrigation system is already in place and on one valve, you can compensate by changing the number and/or size of the emitters, hand-watering smaller plants that cannot survive longer frequencies or plugging all emitters around your trees and using soaker hoses instead, and by increasing the mulch around smaller plants to slow evaporation (keep organic mulches three to four inches from plant stems in order to avoid rot and rodent damage).
Move the emitters out as the plant grows. Roots near tree trunks do not absorb water. After a plant is established, water at the outer edge of the plant drip line where the feeder roots are concentrated. If it rains onehalf inch or more, skip the next interval. Water plants in sandy soil more frequently than plants in clay soil.
If you are adjusting your irrigation seasonally, then continue to do so. If you are not, then start by following the seasonal guidelines above and reduce your landscape watering by 30 to 50%.