Sacramento Digs Gardening Article
Your resource for Sacramento-area gardening news, tips and events

Articles Recipe Index Keyword Index Calendar Twitter Facebook Instagram About Us Contact Us

Citrus trees, beloved and bewildering

Sacramento Digs Gardening
BY Kathy Morrison PUBLISHED JUN 11, 2020

That little orange is doomed -- sustenance has been cut off by the tree and it

will fall off soon. It's "June drop" time. (Photos: Kathy Morrison)

Home garden favorites have a range of quirks

Question: How is an orange tree like a pet cat?

Answer: You love it, even though you don't understand it most of the time.

Really, every lemon, orange, lime, grapefruit and mandarin sold to backyard gardeners should come with an instruction booklet -- or, more realistically these days, a YouTube mini course.

Right now, orange tree owners are flummoxed by a regular occurrence: the "June drop" of excess tiny fruit.

"Aw, gee, look at all these oranges falling off! Must be something wrong. Or maybe it's the weather."

Nope. It's normal. The tree is self-selecting how many oranges it can grow this year. It'll drop as much as 95 percent of the blossoms and fruit it had in spring.

With thanks to UCCE master gardener Bill Krycia, whose citrus class I took in April, here are five more fascinating, flummoxing facts about citrus trees:

1) Commercially sold citrus trees in the U.S. are grafted onto rootstock for hardiness and better production. But the rootstock can and will take over the tree if you let it. Example of the reaction when this happens: "My lemon tree was great for years but now it's producing these bumpy thick-skinned lemons." A significant part of the tree probably died back for some reason -- frost, maybe -- and suckers from the rootstock have taken over. The weird fruit is from the rootstock.

(P.S. The rootstock used for dwarf citrus is called Flying Dragon. I love that name.)

Can't thank the bees for these beautiful navels-to-be,
on the same tree as the one above. Navel oranges

do not depend on pollinators to set fruit.

2) Bees do not pollinate navel oranges. Navel oranges are parthenocarpic (Satsumas, too), meaning they set fruit without pollination or fertilization. All those early blossoms are merely floral -- fun for bees! The later blossoms produced by the tree are the ones that turn into oranges. Seedless oranges, of course. Yes, weird.

3) Citrus trees are evergreen -- they don't drop all their leaves in fall, like apple or pear trees -- and the leaves are multi-taskers. They make food for the tree via photosynthesis, of course, but their additional role is storage. Along with the twigs, branches and roots, the leaves also store excess food (aka photosynthate) through winter. These storage sites are most packed in late winter and early spring, just before spring bloom. This is why citrus shouldn't be pruned then: The fruit yield will be much lower.

4) Citrus varieties easily cross, and the origin of certain varieties is not certain. But this also means new hybrids are being created all the time, especially at UC Riverside, a hotbed of citrus research. The red-fleshed "Valentine" pummelo, for example, is the result of a UCR cross of a pummelo, a blood orange and a mandarin.

5) Some citrus trees, especially mandarins, produce in two-year cycles, with a heavy crop one year, followed by a lighter one. Pruning the tree during the summer before the heavy crop ripens actually can even out this cycle, but who's willing to sacrifice that crop? I know, I know, but do prune if the tree is overburdened and the limbs could break.

For more on growing citrus in the Sacramento area, check out this Garden Note 127 from the UCCE master gardeners.

Comments

0 comments have been posted.

GENERAL GARDENING

An article about gardening.

Keywords:

citrus gardening Sacramento pruning rootstock citrus fruit citrus problems pollinators citrus trees

Newsletter Subscription

Sacramento Digs Gardening to your inbox.

Taste Spring! E-cookbook

Find our spring recipes here!

Local News

Thanks to our sponsor!

Sites We Like

Garden Checklist for week of May 12

Get your gardening chores and irrigation done early in the day before temperatures rise.

* Plant, plant, plant! It’s prime planting season in the Sacramento area. Time to set out those tomato transplants along with peppers and eggplants. Pinch off any flowers on new transplants to make them concentrate on establishing roots instead of setting premature fruit.

* Direct-seed melons, cucumbers, summer squash, corn, radishes, pumpkins and annual herbs such as basil.

* Harvest cabbage, lettuce, peas and green onions. This heat will cause leafy greens and onions to flower; pick them before they bolt.

* In the flower garden, direct-seed sunflowers, cosmos, salvia, zinnias, marigolds, celosia and asters.

* Plant dahlia tubers. Other perennials to set out include verbena, coreopsis, coneflower and astilbe.

* Transplant petunias, marigolds and perennial flowers such as astilbe, columbine, coneflowers, coreopsis, dahlias, rudbeckia and verbena.

* Keep an eye out for slugs, snails, earwigs and aphids that want to dine on tender new growth.

* Feed summer bloomers with a balanced fertilizer.

* For continued bloom, cut off spent flowers on roses as well as other flowering plants.

* Got fruit trees? If you haven't already done so, thin orchard fruit such as apples, peaches, pears, pluots and plums before they grow too heavy, breaking branches or even splitting the tree. Leave the largest fruit on the branch, culling the smaller ones, and allow for 5 to 6 inches (or a hand's worth) between each fruit.

* Thin grape bunches, again leaving about 6 inches between them. For the remaining bunches, prune off the "tail" end, about the bottom third of the bunch, so that the plant's energy is concentrated in the fruit closest to the branch.

* As spring-flowering shrubs finish blooming, give them a little pruning to shape them, removing old and dead wood. Lightly trim azaleas, fuchsias and marguerites for bushier plants.

* Add mulch to the garden to help keep that precious water from evaporating. Mulch also cuts down on weeds. But don’t let it mound around the stems or trunks of trees or shrubs. Leave about a 6-inch to 1-foot circle to avoid crown rot or other problems.

Taste Summer! E-cookbook

Find our summer recipes here!

Taste Fall! E-cookbook

Find our fall recipes here!

Taste Winter! E-cookbook

Find our winter recipes here!