The thought of homemade orange juice, lemonade and limeade may prompt you to plant citrus trees. Preferring the warmer climates in U.S. Department of Agriculture plant hardiness zones 8 through 10, citrus trees typically require a minimum of 6 feet between each trunk so there is room for the canopies to spread. However, planting citrus trees too close together produces a number of different problems.
Decreased Fruit Production
Citrus trees planted close together eventually form an overhead canopy that is completely intertwined, with fruits and foliage along each canopy's original edges subjected to constant shade within this floating hedge. As a result of the shading, fruit production is decreased. The leaves cannot efficiently photosynthesize to produce fruit. The trees may even cease to produce fruit if the canopy continues to grow denser.
Soil Nutrient Depletion
Like most plants, citrus trees need a lot of elemental nitrogen for normal growth, flowering and fruit production. As the roots extend deeper into the soil, the closely planted trees compete for limited nutrient resources. Depleted nutrients tend to display across the tree's foliage and you may see yellowing or wilted leaves across the canopy. Fertilizing the soil helps the trees remain in a balanced state when planted closely. Citrus trees prefer a high-nitrogen fertilizer, such as 2-1-1, but overfertilizing becomes an issue if you are constantly battling poor soil conditions.
Combining lack of soil nutrients with only dappled sunlight is a recipe for stunted citrus tree growth. You may notice that the citrus trees' foliage begins to shrink from its original size and the yearly trunk growth tapers down. Because the tree cannot make enough energy because of competition for sun and nutrients, the plant responds by conserving what little energy it has and channels it into basic survival needs, like photosynthesizing.
An established group of citrus trees planted close together creates a transplanting nightmare because the underground roots and canopy limbs are effectively bonded together. If you need to transplant one of your citrus trees, the roots require cutting so that they are separated from the surrounding trees, along with the intertwined canopy limbs. Removing and damaging roots places stress on the tree, along with the physical transplanting process. As a result, your tree may not survive the move due to the immense stress and damage to the roots and limbs.
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