- Author: Anne Schellman
- Author: Ed Perry
Our UC Master Gardener Help Line often receives calls about citrus. Here are five commonly asked questions about how to care for this juicy, delicious fruit tree.
- Why are the leaves on my orange tree turning yellow?
It's common for citrus tree leaves to turn yellow in winter*. Fertilize to provide the tree with nutrients now, then watch as leaves green up in spring. Avoid fertilizing in fall, which encourages new growth favored by pest and can leave the tree susceptible to frost injury.
- How do I know if my oranges are ripe/when should I pick my oranges?
Oranges are ripe when (drumroll please) the fruit...
- Author: Ed Perry
Our Master Gardener Help Line has received several calls this past month from gardeners concerned about citrus trees turning yellow. An article entitled “Yellow Citrus Leaves in Winter Usually Not a Disease,” written by Craig Kallsen, retired Citrus Farm Advisor in Kern County, does such a good job explaining the problem that I asked for and received his permission to reprint his entire article, presented below.
For many in California, the backyard orange or grapefruit tree is almost a member of the family, and any negative change in its appearance elicits concern. One such change in appearance is leaf yellowing and drop that often occurs during the winter in citrus. Citrus leaves can remain on the tree for as long...
- Author: Jules Bernstein, UC Riverside
![Nursery tech harvesting budwood from mother citrus trees](/blogs/blogcore/blogfiles/92099small.jpg)
Sweet Mother Orange Tree released from quarantine
The 1000th tree okayed for growing by California's Citrus Clonal Protection Program happens to be the oldest living orange variety in the state.
The program, housed at UC Riverside, is the first of its kind in the world. It began in the 1950s, and its scientists spend up to three years testing and clearing citrus trees of disease so they can be released to commercial and private growers.
By law, every citrus tree newly propagated in California can be traced back to one mother tree created at UCR through the protection program. Program Director Georgios...
/h3>- Author: Pamela Kan-Rice
![Cara Cara is the variety of navel oranges currently most commonly planted in California. Photo by Beth Grafton-Cardwell](/blogs/blogcore/blogfiles/86139small.jpg)
A new study outlining the costs and returns of establishing and producing navel oranges with low-volume irrigation in the southern San Joaquin Valley has been released by UC Agriculture and Natural Resources, UC Cooperative Extension and the UC Davis Department of Agricultural and Resource Economics.
“A cost study gives a ‘new' grower a better idea of all the costs that are involved with producing the crop,” said co-author Greg Douhan, UC Cooperative Extension citrus advisor for Tulare and Fresno counties.
Real estate agents, land leasers, bankers evaluating loan applications and others can use the cost study to estimate current costs to plant...
- Author: Ed Perry
Splitting of navel oranges is a disorder that shows up every few years in the Northern San Joaquin Valley. It's difficult to predict the problem, and once you see oranges beginning to split, it's too late to do anything about it. However, it may be useful to talk about why splitting may occur, and what you can do to help lessen the problem.
While you may not notice it until the fruit begins to ripen, splitting in navel oranges begins in green fruit. The split usually starts at the stylar or navel end of the fruit, the weakest point in the rind. The split may be short and shallow, or it may be deep and wide, exposing the segments. Splitting is most serious in navel oranges, but it may occur in Valencia oranges...