One very popular concept for water-wise landscapes is grouping plants according to their water requirements. This not only allows for efficient irrigation, it also helps the plants grow better with fewer problems.
Although there are many ways to classify plants, the following divisions give convenient and water-saving ways to place them in the landscape:Plan the landscape by grouping plants with similar water needs together. Zoned irrigation or hydrozoning is the most efficient way to irrigate and matches plants with similar moisture requirements.
Reducing overwatering and runoff saves water and money, and fewer plants develop diseases from overwatering.
Hydrozoning is based on people and their interaction with the landscape. Areas of high activity create more contact and interaction with plants. This requires more supplemental irrigation to support these plantings. Areas of less activity require fewer plants and less supplemental irrigation.
Generally, there are four potential hydrozones found in a landscape: The principal hydrozone (one or more irrigations per week) is the area of greatest human activity and interaction with the landscape. The high-traffic area is functionally and visually important because people will walk, sit, play and relax in the plant environment.
It is referred to as an oasis in landscape design and, like an oasis in the desert, it is the area of greatest water use.
The secondary hydrozone (two irrigations per month) is visually important to the landscape but has less human traffic and interaction. These areas are more passive in use and delineate space and design. Flower and shrub beds or specimen plants are examples of medium-water use plantings found in a secondary hydrozone.
The minimal hydrozone (one irrigation per month) contains plants that require minimal water to survive the existing climatic conditions.
These areas get infrequent contact with people and are less visually important in the landscape.
Buffer zones, secluded or screened views, parkways and embankments are examples of this zone. Typical vegetation in this hydrozone includes low-water-use and drought-tolerant trees, shrubs and ground covers.
The elemental hydrozone (no irrigation) includes natural plantings that are capable of surviving with available natural precipitation. No supplemental irrigation is applied in this zone after the plants are established, and plants seldom, if ever, come into human contact or activity.
Utility areas and mulched, native plantings are examples of this hydrozone.