20 Feb Organic Solutions: Our Troubled Tangerine Checks Into Tree-Hab

Our tangerine tree isn’t looking so spritely these days. Over the past few months it’s developed a pale, stricken look that has caused some freak-outs (code orange!) here in our garden. Ryan saw the problems first: the cracks and splotches on the trunk, the formerly dark emerald leaves now washed out and yellowy. And yet, like clockwork, it still produced delicious fruit this winter. What gives?

Over the past few months, our tangerine tree has taken on an alarming appearance: leaves have yellowed, branches are defoliating and sap is coming out of the trunk. And yet it continued to crank out juicy winter fruit. This photo was taken in November.

Our citrus tree bark is cracking and sapping.

Here, woolly aphid residue is discovered along the underside of this branch.

Our tangerine tree in January just prior to treatment.

Bugs, explain yourselves. In addition to suffering from inadequate hydration and fertilization, our tree is being vandalized by pests: scale (visible above), woolly aphids and spider mites in particular.

Was our tree being suffocated by the renter-friendly “citrus lounge” we built on top of it? If so, why is the orange tree right next to it thriving?

Guilt spiral, guilt spiral, guilt spiral…

Luckily, we ran into Tyler Trimble, the founder/owner of Backyard Fruit San Diego, which offers consultations, grafting, installation and regular maintenance for fruit trees. We contracted his services, and Tyler came to the house for a full examination.

The main culprits behind our tangerine troubles? Inadequate watering and fertilization, and a full-fledged bug infestation. The pests in particular: scale, woolly aphids and spider mites. During his visit we established, and even got started on, a course of treatment that includes an organic spray and fertilizer, some serious pruning and a new approach to watering. Details below!

Tyler Trimble, founder of Backyard Fruit San Diego.

“Fruit trees are great parents — they will steal everything from the soil and from themselves to put directly into the crop,” Tyler explained.

Then he gave our tangerine tree the “me” time it deserves, spraying the leaves with a sesame and fish oil mixture. This organic solution is intended to suffocate the eggs of the invading insects while killing the adults; it’s non-toxic to beneficials like bees and butterflies. The treatment made our place smell like a sushi restaurant at first, which was great…until it lingered so long that our place smelt (ha, get it?!) like a high-end fish market for the next day or two.

Tyler sprayed our tree with a mixture of organic sesame and organic fish oils to kill bugs, eggs and larvae. The proportioner sprayer simplifies the dilution process.

But anything for our poor baby tangie. Tyler recommends spraying this oil every ten days, three or four times while the problem persists, then giving the tree a stern jet of water once a month to blast out some of the debris, like cobwebs and dead leaves, that accumulates in the canopy. We used our pressure washer at a safe distance for this task and we could almost hear the tree let out a sigh of relief.

Longer waterings have been added to the regimen as well. (Too little, too often is apparently a common watering mistake.) We will also be adding Dr. Earth’s Nitro Big foliar spray once a month to the leaves and Dr. Earth’s fruit tree fertilizer (7-4-2) to the soil every six weeks to two months. In fertilization, timing is key: “Try not to feed too heavy when trees are in full bloom,” Tyler said. “Do it just before or after bloom to avoid losing fruit. If we feed too heavily when the tree is in flower, it can cause the flowers to fall or abort mission before becoming fruit, especially when using higher nitrogen foods.”

Tyler, balancing atop our ladder, demonstrated how to properly remove dead branches. As far as pruning goes, Tyler said, “It’s really important to make clean, flush cuts without leaving stubs, [that is,] one- to four-inch branches with no new growth. Stubs die and become houses for termites and other insects. When pruning, try to leave eight inches long or more so it can regenerate. Making clean cuts will promote new growth and keep the tree healthy.”

Tyler schools us on proper pruning.

Our Tangerine Treatment Plan:

– Pick all the fruits, which divert nutrients from the foliage.

– Spray with organic sesame oil/fish oil mixture (to kill pests and their eggs) every 10 days for as long as the problem persists.

– Fertilize soil with organic citrus tree fertilizer followed by deep watering.

– Speaking of hydration, we’re now watering the tree once a week for 30 minutes.

– Three days after applying oil spray, blast the canopy with a jet of water to remove accumulated debris, followed by Nitro Big foliar spray.

– Prune dead branches — Tyler started it for us, and we need to finish the job.

– Paint the trunks with a water-based latex/acrylic paint (diluted to 50%) to prevent sunburn and bug infestation. (Pending landlord approval.)

To ensure that our artificial turf was not smothering the tree’s shallow root system, we dug five channels three inches deep beneath the turf and buried a drip irrigation system inside the channels.

After Tyler left, we applied a nitrogen-rich fruit tree fertilizer to the soil to help bring back lush growth to our tree’s canopy. We distributed the dry fertilizer over the gravel channels and sprayed it down with a hose to assure absorption into the soil. We then followed it up with a 30-minute deep watering using our drip irrigation system.

Our guilty-parent feelings aside, it was a thrill to have a plant expert here in our garden. Tyler grew up on his family farm in Arizona, and now grows over 45 trees in his own yard here in San Diego.

“Trees have a lot of heart,” he said. “I have seen trees come back from the dead many times. With a little love, luck and know-how you can save most younger trees, and about half of older trees, with some exceptions.”

And the ones that do die? Overwatering and planting too deeply are the two main causes in Tyler’s experience. His favorite fruit is the nectaplum, which has purple leaves that fade to dark green. The baseball-size fruit is, taste-wise, “a great plum/nectarine balance. Everyone says it’s the best piece of fruit they’ve had in years.”

That’s the kind of reaction that inspires Tyler to do what he does. “My overall mission is to teach people where their food comes from,” he said. “To get children excited about eating fruit, to teach them that fruit can be better than any piece of candy. Also to educate about organics, protecting the balance of life and this Earth we all live on.”

—TH

Mid-February 2014. Tangerine tree, let’s do this.