A Southern California nursery specializing in trees recommends fertilization tips for normal and drought conditions.
Fertilizing typical and drought-tolerant trees in the landscape requires a knack for applying in the right season, proper administration and for using the best product for the tree. Fertilizer is often misunderstood and misused. Fertilizer is not really direct food for trees, but instead, a boost to your trees providing the ingredients needed for photosynthesis and growth. Fertilizer should not only be used when minerals are lacking or absent in the soil but also to maintain a good chemical balance within the soil all year long. Your top ten, typical choice of standard trees for most landscapes range from King and Queen palms to Agonis, Magnolia and Lagerstromia varieties. Drought-tolerant trees can be fertilized much in the same way. These trees should be fertilized on a regular schedule, depending on the geography and status of the tree. Trees in areas that receive a lot of rain usually have a lot of natural nutrients in the soil and only require about one to two times a year of fertilizer application. However, in more arid areas, like the Southwest, you should fertilize up to three times a year to produce more nutrients in the soil and to keep the plant healthy in each season. The best times for fertilizing is in early spring, mid-year and in the fall. The early spring is a good time because tree roots are coming out of the dormant period and require a boost to be healthy as they are starting to grow. Mid-year is also important because trees are experiencing more heat, absorbing water faster because of the heat and therefore going through nutrients quicker. To put in fertilizer during this time gives the tree a boost and replenishes those nutrients lost. During the Fall, tree roots have cooled a bit but there isn't as much rainfall as during winter months. Avoid fertilizing trees and shrubs stressed by drought during the summer months. If water is unavailable, do not fertilize at all because plants will be unable to absorb the nutrients.