Column: The Garden Girl – Citrus

September 13, 2015 17:57 pm · 9 comments


Claycord’s citrus shrubs and trees are in need some tending too this month.

Citrus plants (especially installations less than five years old) can be suffering from yellowish leaves, erratic fruit/flower drop and pest damage during these last days of summer.

It is time to help your citrus shrubs and trees by fertilizing.

Fertilizing will encourage greener leaves and aid in the maturing and sweetening of young fruit.

Summer stress can take its toll on citrus. Long days of hot temperatures and drying winds combined with water rationing can lead to citrus displaying curling, pale leaves that are desperate for nutrients to replace those that were evaporated out by the season.

One must evaluate the condition of their citrus before they fertilize. How yellow or green are the leaves? When was the last time you fertilized? Is there any fruit forming?

Citrus that has green leaves and developing fruit should be fertilized with a formula to encourage large, juicy, sweet fruit. Look for formulas that have lower nitrogen than phosphorus and potassium. Ideal formulas are 3-20-20 or 2-10-10 if choosing a water-soluble fertilizer and 0-10-10 if using a granular fertilizer. How you irrigate your citrus will determine the type and application of fertilizer you use. Those that water with a drip system will need to fertilize with a water-soluble fertilizer. Folks that irrigate with sprinklers or hand water have the luxury of using a granular fertilizer.

Citrus that has yellowing leaves should be fertilized. Use a fertilizer formula that reads 7-3-3 or 8-4-4. The first number in both of these formulas represents nitrogen. This amount of nitrogen hopefully won’t initiate fruit drop.

If you have yellow leaves on your citrus and you have fertilized within the past month, you should consider applying a dose of iron. Chelated Iron is a great choice to use for fast greening of leaves. You can apply it directly to the leaves as a spray, or water it in. Follow the directions on the label.

Let’s say your citrus looks awful. The leaves are yellow, curled and your shrub or tree shows no signs of any fruit. If this is the case, fertilize with a dose of multi-purpose fertilizer. Look for a 16-16-16 formula and follow the label directions. You can use a higher percentage of nitrogen here since your citrus is in such distress.

Pests can be a big problem on citrus towards the end of the summer. Scale and leaf miners can infect healthy looking plants fast. Scale is a hard-shelled insect that attaches itself to citrus stems, wood and the backs of the leaves. You will probably notice ants on your citrus before you actually see the scale. Control scale by removing highly infected branches, spray shrubs with Neem Oil and use an insect barrier like Tangle Foot to prevent the ants from traveling up the plants. Leaf miners were a nuisance last year, and we’ve seen traces of the pest this year.. Leaf miners are tiny, caterpillar looking larva that mine there way within the layers of your citrus leaves. One they are present, you simply need to cut the tips of the stems off of the plants. Spraying isn’t an option, since the problem is within leaf.

Growing citrus can be hard the first handful of years, by eventual yields are worth all the work. Nothing beats a juicy, homegrown orange.

Happy Gardening.

Nicole Hackett is the Garden Girl at R&M Pool, Patio and Gardens, located at 6780 Marsh Creek Road in Clayton, 925-672-0207.

kelly September 13, 2015 at 6:30 PM

Thank You Garden Girl.

I am worried about my orange tree. Not sure when it is supposed ro bloom this is only my second year living here. But I think last year at this time I had hundreds of flowers right now their are two baby oranges on the whole tree. Hopefully it will still bloom and give me more oranges.

Last year I remember you said not to feed them any Nitrogen because it will cause the blooms to fall off.

Was wondering if there was anything I can do to encourage the tree to bloom.

Thank You so much.

kelly September 13, 2015 at 6:38 PM

The tree is about 15 feet tall, is it better to feed by spraying the leaves or should I feed the roots. I have heard that on large trees the roots are so deep the fertilizer will not reach them.

anonmtz September 13, 2015 at 7:13 PM

Thanks for this…..timely and thorough.

Leela September 13, 2015 at 7:14 PM

This spring I planted 20 seeds from a lemon fruit I bought at the store. 4 of the seeds have sprouted. 2 are about 14 inches tall and 2 are about 12 inches tall. They look green and vigorous. What should I do for them as we get into fall?

quaddmg September 13, 2015 at 8:33 PM

Thank you for posting this. I recently adopted a few different citrus trees and noticed some yellowing of the leaves within the past week. I thought I wasn’t watering enough. I’ll make a trip for some fertilizer this week. Very informative post, thanks again!

Rich September 14, 2015 at 8:08 AM

In April, I starting using recycled water, and the Lemon and Tangerine trees leaves, turned bright green from a yellowish color. Seems like more fruit has set than usual…

Mary Fouts September 14, 2015 at 12:33 PM

@Rich #5 – I had the exact results using recycle water on my small orange tree, similar results on other trees including 4 cedar redwoods. The orange tree has never looked better including more fruit setting on, seems to really like the higher mineral content of the recycled water.

misterb September 14, 2015 at 7:47 PM

Not citrus, but “end of a stressful summer” question …

My hydrangeas have suffered during the heat & water situation this year (pitiful flowers and leaf loss) and I would like to put them put of their misery for the year. Is it appropriate to cut them way back now as if it was the end of their season?

Garden Girl September 15, 2015 at 4:44 PM

Hi misterb,
I’d let the look as they do. If you prune your hydrangeas hard now they may try to grow and new growth is suseptable to frost. You can deadhead though.
If you want to do something for them, spread some soul conditioner at their feet.
Feed your hydrangeas in mid February with a granular acid fertilizer, and give a dose of granular iron too.
Thanks for the question.

Hi Leela,
You’ll need to protect your young seedlings from frost.

Hi Kelly,
A 15′ citrus may it even need to be fed. If your tree looks good, nice dark green leaves and a good fruit set, you’re probably fine.
I would feed at the bottom of the tree, throughout the tree’s drip line.

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