Citrus: Things which affect blooming and fruit set

Published 12:00 am Saturday, February 4, 2012

As we approach warmer days and the end of the severe cold weather, it is important to remove the citrus from your tree so the tree can rest and prepare itself for another fruitful year of production. Fruit should be removed from most all of the citrus trees except lemons and the late bearing citrus types like Moro oranges.

Lemons are ever-blooming, which means they may bloom throughout the year as long as the conditions are right. There may be some lemons on the tree that have been ripe for several months, and there may be some lemons that are still green, a sign that the tree may have bloomed at another time other than the usual early spring blooming. Remove the older lemons from the tree, but leave the smaller, green lemons. If there are other ornamental citrus trees that are late ripening like Moro oranges, which ripen in late December and January, do not remove the fruit from these trees. Leave this fruit on the tree until it ripens, and then pick it within a few weeks.

The cold temperatures we have been having followed by the unusual warm temperatures will cause the ripe fruit to get soft and later rot on the tree. This may attract insects that may damage the other fruit. The main problem with leaving the ripened fruit on the tree too long is it may delay the blooming of the tree for the next fruit crop. It may also cause the tree to bloom very little and even set less fruit from the blooms that it has produced.

Another problem that sometimes affects citrus trees and the amount of blooms they produce and the amount of fruit the trees set is the timing of the fertilization. Never fertilize a citrus tree when it is blooming because this will cause the citrus tree to go into vegetative production, production of leaves and limbs, and the tree may not set as much fruit. Fertilize the tree before it blooms, or wait and fertilize the

tree after it has set its fruit. Citrus trees are fertilized at the rate of one to one-and-a-half pounds of 13-13-13 per year of age of the tree or per inch of diameter of the trunk of

the tree. Trees that have been

heavy fruit producers may require the top amount of fertilizer, while trees that have not produced well may require a lesser amount of fertilizer.

If a citrus tree is trimmed severely, this may also affect the blooming of the tree. With citrus trees, when a tree is trimmed, it causes the tree to start producing more leaves and limbs. When producing more leaves and limbs, the tree will not produce as many blooms, and it will not set as much fruit. Trimming one side of a citrus tree also causes more growth on the other side of the tree, so only trim the tree if it is really needed.

The condition of the tree may also affect the blooming and fruit set.

A tree in poor condition will not bloom as much nor set as much f

ruit as a tree in good condition. If the tree has very few leaves, it may have suffered cold damage, or

more likely the tree is suffering from insect damage. It is important to follow the recommended insect control recommendations for


Insect as well as fertilization recommendations can be found in the back of citrus publication 1234 – Louisiana Home Citrus Production. This publication can be found at your local LSU Ag Center Parish Office or on the LSU Ag Center’s website at For more information contact your local LSU Ag Center parish county agent.

If you have any questions, please contact your local LSU Ag Center County Agent. You can contact David Pichon, County Agent-St. John Parish at 985-497-3261 or by email at