The controller views plant type as a percent of the daily ET. This is known as the landscape plant coefficient. Agriculture uses crop coefficients to know what percent of the daily ET a crop needs returned, the same as SmartLine looks for plant type in determining what percentage of the daily ET needs to be replaced. This is not new information; farmers have been using crop coefficients since the early 1900’s.
With SmartLine, each plant type refers to a specific percentage. We set 100% as cool season turf mowed at 4-6 inches as the base coefficient. The chart below outlines what each setting refers to, plant-wise, and the landscape coefficient it represents.
| CTURF | Cool season turf (fescue, ryegrass, bluegrass) | 80% of ET |
| WTURF | Warm season turf (Bermuda, St. Augustine, Zoysia) | 60% |
| SHRUBS | Shrubs (typical localized shrubs for your area) | 60% |
| ANNUALS | Annual color (seasonal color - flowers) | 100% |
| TREES | Trees (typically new plantings of local tree species) | 80% |
| NATIVE | Native plants (drought tolerant plants, established shrubs) | 25% |
You also have the option of selecting the landscape coefficient yourself as a percentage of 10-300%. This allows you to tailor the needs of a zone that may have 2 or more different species of plants with different water requirements. As always, it is a best practice to hyrdozone properly to prevent overwatering some plants due to their location.
Hydrozoning
Hydrozoning is where we get the most questions. “What do I do when I have shrubs and annuals?” There are many instances where annual flowers are incorporated into an existing zone of shrubs. Sometimes these are done after the installation, sometimes as part of a landscape plan. In most instances, the flowers will need more shallow and infrequent water to maintain color and vigor than established, mature shrubs.
What to do?
Separate the zones based on the plant type in the irrigation system. Typically, color areas are much smaller than the larger shrub or turf zones they exist in. Simply adding a new zone for the color areas allows for you to water the proper amount only in the annual area and not overwater the turf or shrubs. By selecting the proper plant type, we are programming the controller to know what it has to use in determining the needed irrigation to be returned to the landscape. Plant types vary by landscape and some incorporate more elaborate and unique plants that may be shrubs by description, but require the water of annuals. Always consult a landscape professional if you have any questions about the plants in your landscape and their irrigation requirements.