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How to select the best citrus tree for your SLO County yard

A lime tree
A lime tree

Q. I like to grow citrus trees, but live in Santa Margarita. What are my options?

Loretta K.

A. 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 is the least tolerant to freezing temperatures.

To clarify further, Mexican lime trees can be damaged by frost at temperatures below freezing, but kumquats can withstand temperatures to 18-20 degrees Fahrenheit. Consider not only how cold it will get, but also how many days the cold spell might last.

Every citrus tree has two parts — the lower part is the rootstock; the top part, the scion, is grafted on and bears the citrus varietal name you buy.

The rootstock determines fruit production, size of fruit and size of tree, tree vigor, resistance to soil-borne fungal diseases, nematode and virus susceptibility, and of course, cold hardiness. It’s best to seek expert advice on which rootstock is 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 buy from a reputable nursery because its shipments are inspected and verified by county agriculture 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 such as 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 from 10 a.m. to noon on Saturday, July 15, in our demonstration garden at 2156 Sierra Way, San Luis Obispo. 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.

Jutta Thoerner is a UCCE master gardener.

Got a gardening question?

In San Luis Obispo call 781-5939, Arroyo Grande, 473-7190 and Templeton, 434-4105. Visit us at http://ucanr.org/sites/mgslo or email us at anrmgslo@ucanr.edu. Follow us on Instagram at slo_mgs and like us on Facebook. Informative garden workshops are held the third Saturday of every month, 10 a.m. to noon at 2156 Sierra Way, San Luis Obispo. Garden docents are available after the workshop until 1 p.m. To request a tour of the garden, call 781-5939.