Yellowing of leaves on Oro Blanco

I planted an Oro Blanco last fall and its leaves have been slowly turning yellow since then. It is in the most sunny part of the yard and receives easily more than 8 hours of sun (unless its gloomy like the last few days). I initially thought the cold might be the reason and it may revert back to green in spring but it hasn’t happened so far. I did see a flush of new shoots with greener leaves this year. However, even those leaves are slowly becoming yellow now. Since the end of Feb, I have been doing monthly application of Vigoro citrus fertilizer (6-4-6) at recommended amount for a new tree (1 2/3 tsp). I am yet to see an improvement

Here is the new growth from this year

Closer look at couple of the older leaves

From what I read ( this is either nitrogen deficiency or overwatering/root rot. I did see a few leaves fall last year but the tree seems to be actively growing and even has a few fruits set. Also, I have a Owari Satsuma less than 10 feet from this one on the same watering and fertilizing schedule and it has dark green leaves and doesn’t have any of these problems. I see quite a lot of posts in Houzz on the same issue (including @hoosierquilt), but I don’t see a resolution.

Is this nitrogen deficiency? or any other trace minerals? does it need any special application like vinegar with water? The spring has been quite wet so far this year. Will it be better once the weather heats up later? I could use an expert opinion here, thanks!

Many of the threads on this topic I found here and in Houzz didn’t have any solutions or at least no record of which ones worked. I contacted @Richard offline and his advice was to cut down on the watering as the tree might be overwatered. I did so and I think the combination of reduced watering and the warmer temps is making a difference. Here are the before and after pics.

Before (May 2019):

Now (July 2019):


I’m having this exact problem right now. I planted an oro blanco last year and my tree currently looks like your May photo. It is also covered in blooms! How often were you watering until May? What about after? I water 1-2x a week. I’m wondering if I should give it some nitrogen heavy miracle gro.

I thought my tree lacked nitrogen and was feeding and watering it every week. I read that its best to water deeply at the time of applying the fertilizer. Last year, we had a long and wet spring, so the tree was obviously getting over-watered. If you want to feed your tree, best to do foliar feeding until summer to not over-water during cooler spring weather. Other than feeding and watering the trees once in late Feb and late April, I usually resume watering only in June (once in 10 days) or if there is a hot spell before that. I’d only get to 2x a week in the heights of summer when the temps are in the 90-100s. However, I am not an expert on this.

Also, I learnt that citrus do show some transplant shock right after planted and after the first winter. So, chances are with some foliar feeding and warm weather, your tree should be back to lush green growth soon. I’d think majority of the fruits in the first year to help the tree, but you can wait until later as many fruit buds will drop anyway.

Thank you. Is there a foliar feeder that you like to use?

I used fish and seaweed spray last year. Most fertilizers have a foliar feeding dosage recommendation in the package, I think. This year, the spring rain ended early in April, so I didn’t use any foliar fertilizer

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Inground citrus trees don’t need a lot of care but they do like nitrogen. If your soil is too alkaline, that they don’t like.P/H 6 or 61/2 is needed. Keep mine at 51/2, mostly rainwater, mix with some well water.

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I’m having the same issue with my newly bought oro blanco tree on my balcony. What amount of watering is necessary for a tree that’s approximately 3-4 feet tall? I’ve filled up my watering can about 1 cup.

I am assuming you are growing it in a pot. It is a totally different calculation compared to estimating water for an in-ground tree (which mine is). I don’t grow much in pots, other than ones waiting to be planted. So, I may not be the right person to answer, but I’d water whenever the soil just beneath the top is dry. That could be anywhere between once in 2-3 days during summer (once a day during heat waves) here in the bay area and almost once every week during the spring/fall.

Also, I noticed that pomelos (in my experience of growing 4-5 citrus so far) are the hardest hit by transplant shock compared to others. So, first year yellowing of leaves is expected.

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youve assumed correctly it is in a pot. i dont expect it to grow too much since it is in a pot on a balcony. i just want to care for it the best i can. thanks so much for the advice!

Same issue. Planted last May and even now I see no improvement. It continues to bud but leaves are dropping. Here is a photo from today

I should probably try foliar feeding like you suggested. The soil there is always moist because I water when I fertilize and alkaline.