CITRUS FRUIT AND BLOSSOM DROP

Tales from a Desert Gardener
by Steve Fazio, Horticulturist

“My fruit tree is dropping all of its blossoms – my fruit tree didn’t bloom this year – fruit is falling from the tree.” These remarks are expressed by many gardeners in connection with citrus and deciduous fruit trees. What caused these problems? Some are related to cultural management practices, temperature; others are normal plant responses.

Citrus trees will cause the greatest concern for most gardeners – they will shed many blossoms and later in the season, fruit as large as walnuts will fall to the ground. All varieties of citrus produce more blossoms than the tree can possibly set – approximately 98% will fall even under the best cultural management practices. If 2% of the blossoms set fruit, this would be considered a heavy commercial crop. This is a natural behavior of the trees, but failure for 2% to set fruit is related to many factors. Late spring frost that occurs during bloom period causes a weakening or death of the abscission layer. This layer of cells connects the flower to the tree – sub-freezing conditions injure the cells, and blossom drop will result.

Trees that were not fertilized prior to the bloom period often drop excess number of blossoms, especially if soil fertility was extremely low. The tree is reacting in a natural manner – it is ridding itself of a burden. Improper irrigation is also responsible for blossom drop. Fruit trees in the blooming stage require very special attention in connection with soil moisture – they should never be allowed to stress for water – this will weaken the connecting layer. Trees should not be over watered at this stage – irrigation should be maintained on the same level used during the growing season – irrigate when soil examination reveals a need for moisture, but do it on a more careful basis during bloom.

Some varieties of citrus may fail to produce blossoms – gardeners will often state, “Last year my tree had a profusion of blossoms, and I had a heavy crop of fruit – no blossoms are evident this year.” This condition is common with some varieties of mandarins – the Kinnow mandarin is one of the main culprits. This condition is referred to as “alternate bearing” – a heavy bloom one year and none the next. This occurs on other citrus varieties, but not as pronounced as the mandarins. Commercial growers will often state, “My orange and grapefruit crop is on the light year cycle.” Others may state, “My crop is on the heavy cycle.” Trees that produce a heavy crop one year will usually produce a lighter crop the following year – this is alternate bearing on the light side.

The heartbreak of growing citrus is called “June drop.” This occurs when fruit the size of a pea or as large as a walnut fall from the tree. It is caused by high temperatures and low humidity – it will be evident starting in May and extending through the month of June. Trees should be checked at frequent intervals during the stress period for soil moisture – fruit drop is aggravated by moisture deficiency.

Harlow Gardens
5620 E. Pima St., Tucson, AZ 85712
(520) 298-3303

Comments

  • Posted: August 17th, 20128:07 am
    John C
    Said

    I live in Mesa AZ….This year my navel orange had no blossoms therefore no fruit growing. The leaves look green and shiny. I am expecting that maybe it could have been water as after I watered copiously the trunk sprouted lots of those little outgrowths of leaves.
    My question is this. I do not want to lose this tree. What is the best thing to do now to make sure it will be OK for next year?

  • Posted: August 17th, 201210:29 am
    John C
    Said

    It is a little unclear (not sure about why you were watering ‘copiously’ or exactly what the ‘little outgrowths’ look like) what is happening to your citrus. However, to make sure your tree is OK for next year, simply continue to water on a regular schedule and fertilize around Valentine’s, Memorial, and Labor Day. If you could send us some digital photos at contactus@HarlowGardens.com we could be more helpful.
    Thanks

  • Posted: April 20th, 20154:08 pm
    John C
    Said

    Thank you!
    information was most helpful, you answered my question. I’ll try a better watering & fertilizing schedule.

  • Posted: September 25th, 20157:22 am
    John C
    Said

    My naval and blood orange trees are dropping fruit that are the size of tennis balls. l have lost almost half of the fruit. The
    Trees are in very good condition and this is the first this has happened.

  • Posted: October 14th, 201510:47 am
    John C
    Said

    Hello Glynn,
    Citrus fruit drop this time of year and of the size indicated is definitely unusual. There is a reason but we may not be able to pinpoint it.
    Most fruit drop because the tree is under stress. This could include too much water, too little water, or too much fertilizer. In rare circumstances it could include high winds and hail.
    So, think about whether any of these situations could apply to your situation.
    Thank you,
    Cara Bohardt
    Assistant Administrator

  • Posted: March 11th, 20165:21 pm
    John C
    Said

    I was told by the woman that gave me a small orange tree (30″) that when blossoms start to show, that I should stop watering it or the blossoms would fall off. Any truth?

  • Posted: March 22nd, 20162:50 pm
    John C
    Said

    Hi Larry,
    This is not what we would recommend. Water your citrus on a regular basis with slow deep waterings.

    Thank you,
    Cara

  • Posted: July 8th, 20161:13 pm
    John C
    Said

    I bought a miniature mandarin orange tree online a couple of years ago. This year it had blossoms in early spring, with little fruit growing-then they all dropped off. Here it is July and I’m surprised to see it’s flowering again. I put in a citrus fertilizer stake in the pot a month or so ago. Since I lived in CO now SD I don’t plant my tree outside and have it in a pot in a sunny window But I was disappointed to see my flowers not yet opened dropping to the floor. Is there anything different to do since it’s a house plant? The wind blows pretty much all the time here and the poor little blossoms wouldn’t have a chance outside.

  • Posted: July 11th, 20163:29 pm
    John C
    Said

    Hi Sarah,
    We are not the experts in indoor citrus. Here is a link from our citrus grower that goes over the care of citrus indoors: https://www.fourwindsgrowers.com/tips-and-advice/growing-dwarf-citrus/as-houseplants.html

    Thanks,
    Cara

  • Posted: March 20th, 20171:09 am
    John C
    Said

    I planted a white grape fruit tree 2 weeks ago, the tree is 3 years old, it started to bloom but I hosed it down like rain to get rid of ants going up and all over it so it can be ant free while I was aplying the tape around the trunk to stop the ants from going up, the next day I noticed some of the flowers are dying, do you think I damaged the blossoms?

  • Posted: March 20th, 20179:22 am
    John C
    Said

    Hello Emma,
    Citrus trees drop at least 98% of their flowers. Flowers dying is totally normal. I don’t think you damaged the blossoms.

    Thank you,
    Cara

  • Posted: September 30th, 201711:10 pm
    John C
    Said

    My navel orange tree has yet to blossom. I can’t remember the month it usually has blossomed. Is there stil a chance it will this year? I have fertilized it as recommended and have watered it and it looks healthy.

  • Posted: October 13th, 201711:56 am
    John C
    Said

    Hello Diana,
    You need not worry. Navel Orange trees bloom in February/March. This is the only time of year the bloom. Sounds like you’re doing the right things, so your tree should bloom when it’s time.

    Thank you,
    Cara

  • Posted: November 16th, 201710:45 pm
    John C
    Said

    As a rank amateur at growing fruit, I have just followed what I considered good practice such as “The fruit is sweetest closer to the stem” which is false as the fruit is equally sweet, but good practice for pruning.

    I found your article most informative. However, I live in South Africa so just have to reorganise the months accordingly.

    Sincerely

    Alf T

  • Posted: April 1st, 201811:14 pm
    John C
    Said

    I have 2.5 year old mexican lime and meyer lemon trees in containers (1each) on my roof deck. for the past 2 years the fruits get little larger than BBs and fall off. They are at that stage this year. The growing just stalls. Any thoughts?

  • Posted: April 2nd, 201812:29 pm
    John C
    Said

    Good Afternoon JS,
    Citrus will shed their fruit if they’re not getting enough water. You want to up the frequency of watering as we warm up. You also want to make sure you are feeding a potted citrus throughout the growing season (Feb-Sept). We carry a wonderful organic citrus fertilizer by Down to Earth that has specific directions for potted citrus.

    Thank you,
    Cara

  • Posted: April 14th, 20186:36 am
    John C
    Said

    My citrus trees (all about 4 feet high) had tons of blossums and then we had a heavy frost, not I do not see any blossums. I usually still see blossums and some tiny fruit starting from where the buds were. Is there anything I can do to help get more buds?

  • Posted: April 17th, 20182:20 pm
    John C
    Said

    Good Afternoon Walter,
    Most citrus trees bloom once a year in the late winter/early spring. There is nothing you do to make it bloom again, it’s against the laws of nature.

    Thank you,
    Cara

  • Posted: April 30th, 20188:37 am
    John C
    Said

    My orange tree was planted about 7 months ago or so. It’s about 7’ tall with a trunk diameter of about 2-2 1/2”.I had hundreds of flowers and now I’m down to maybe 20 oranges that are slightly smaller than a marble. Even some of them are turning yellow and falling off. I water every four days. There are three irrigation lines to the tree and each is set to two gallons/hr. The timer is set for 30 minutes. I have watered a few times manually in the past three weeks. When I stick a probe into the soil it slides VERY easily down to about two feet and then stops. Further from the trunk, the probe only goes in 4-5” before stopping. I’ve fertilized three times since the tree was planted and I used citrus fertilizer. In addition to losing almost all of the fruit, I noticed this morning that some of the leaves are curling and yellowing. Suggestions?

  • Posted: May 2nd, 201810:32 am
    John C
    Said

    Good Morning Alan,
    After 7 months your water absorbing roots have drifted away from the trunk towards the dripline (the widest part of your canopy straight down). You want to water deeply especially further from the trunk where the main water absorbing roots are. In addition, 3 gallons of water may not be enough water. Every four days is appropriate this time of year(spring), but I would increase the amount of water.

    Thank you,
    Cara

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