Citrus Trees
By Jutta Thoerner UCCE Master Gardener
I like to grow Citrus trees, but live in Santa Margarita. What are my options? Loretta K.
All citrus is considered tropical, which means they like temperate climates. Your ability to successfully grow citrus will depend on the specific microclimate in your garden. The cold hardiness of citrus varies with the type of citrus you choose. The hardiest species to plant are: kumquat, Meyer lemon, sour orange, tangelo, grapefruit, lemon, Mexican lime and citron. Citron being the least tolerant to freezing temperatures. To clarify further, Mexican lime trees are frost damaged at temperatures below freezing, but kumquats are cold hardy to 18-20°F. Consider not only how cold it will get, but also how many days will the cold spell last.
Every citrus tree is a two-part tree. The lower part is the rootstock; the top part, the scion, is grafted on and bares the citrus varietal name you buy. The rootstock determines fruit production, size of fruit and size of tree, tree vigor, resistance to soil born fungal diseases, nematode and virus susceptibility, and of course, cold hardiness. It's best to seek expert advice on which rootstock will be best suited for your location.
Plant your citrus tree in the fall or spring. With the detection of the damaging pest, Asian citrus psyllid, in SLO county, only purchase from a reputable nursery because their shipments are inspected and verified by County Ag Department officials. At the nursery, look for a healthy tree with deep green uniform leaves, free of blemishes, cuts or nicks on the bark, with no obvious pest damage like chewed leaves. Put your tree on a regular watering schedule and remember that a young tree‘s water requirement is critical until the trunk diameter reaches 1 inch. Consistent and moderate watering is advised. More citrus trees die from overwatering than underwatering!
If you want to know more about both citrus and another tropical plant, the avocado, join us at the UCCE Master Gardeners Advice to Grow By workshop on Saturday, July 15th in our demonstration garden at 2156 Sierra Way, San Luis Obispo, 10am until 12pm. Register on our website - http://ucanr.edu/sites/mgslo/
The garden will remain open and garden docents will be available after the workshop until 1 pm., depending on volunteer availability.