Q: I am looking for the amount of water used by trees. I am assisting a committee in our 50-year-plus homeowners association to determine how much water the established trees are using. If there is a web page or some other compilation I would be grateful. These trees are the main ones: mesquite, oaks, palo verde, ironwood; these multi-branched shrubs are fillers such as Texas ranger varieties, native feather dusters, oleander, and jojoba.
A: How much the plants are using is hard to determine. While some research has been done in this area on crop plants, we donβt have as much information for landscape plants. We have some broad guidelines for watering trees and shrubs based on plant type, their status as native or non-native, and whether they are well adapted to the desert. Google βLandscape Watering by the Numbersβ to see a helpful publication on this topic. The actual needs will be dependent on our overall climate, microclimates where they are planted, and the size of the plants. By following general guidelines for the plant, using a soil probe to ensure water is reaching the correct depth, and looking for signs of desiccation or overwatering, you should be able to get a sense of how much water is required.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions and photos may be emailed to tucsongardensage@gmail.com
