FAQs
These are the more common current questions about selecting, planting and maintaining trees.
What kind of tree should I plant?
What kind of fruit trees can I grow in San Diego?
If I use treated wood around my fruit trees, will the chemicals poison my fruit?
Can you recommend a company where I can buy beneficial insects?
What is the green powdery substance on the trunk and branches of my citrus tree?
What can we do to protect my fruit trees from borers?
What is the Asian citrus psyllid and citrus greening disease or Huanglongbing?
Why are oak trees dying in San Diego County?
Should citrus trees be fertilized this fall?
How do I contact a Master Gardener?
What kind of fruit trees can I grow in San Diego?
San Diego has one of the best climates for all types of fruit, from tropical and sub-tropical types like mangos and avocados to stone fruit like cherries and peaches. Surprising to many, pears and apples also grow fairly very well in our mild region.
For fruits trees to successfully produce most require a certain number of hours of cold temperatures before they will bear. This is called the chill hour and it is an annual requirement. Chill hours vary by region. Expect more chill hours in Julian than Coronado. A broad definition and a table of values for California has been compiled by the University of California Agricultural and Natural Resources Department. Once the number of chill hours has been found, choose a variety of your desired fruit tree that will requires those chill hours or less.
In 1997 the California Rare Fruit Growers of San Diego published a table of stone fruit varieties for milder climates. Many of these varieties are still available. However, as stone fruit is a commodity, new varieties are regularly developed, particularly for southern California. Look at information by commercial growers for current fruit for your local climate. A local nursery should also stock varieties that will do well in your local area.
Borers often attack fruit and ornamental trees that are weak or damaged by sunburn. Live tissue beneath the bark can be killed by heat from the sun on the south side of a tree's trunk and the top side of horizontal branches. The trunk and major branches of newly planted and container grown trees should be painted with whitewash to protect the bark from sunburn damage. You can use a commercial whitewash sold at some garden centers, or you can dilute white interior flat latex paint with an equal amount of water. Also, irrigate as needed to provide adequate soil moisture for young trees. Wait until leaves and shoots are actively growing, then feed lightly with a fertilizer containing nitrogen. Scatter a small amount of fertilizer around the tree at least one foot from the trunk and water well to dissolve.
