Citrus trees (Citrus spp.) include grapefruit (Citrus paradisi), lemon (Citrus limon) and orange (Citrus x sinensis). These fruit trees can be grown outdoors all year in U.S. Department of Agriculture plant hardiness zones 8 through 10. Whether or not citrus trees should be mulched depends heavily on the climate and soil conditions of the region in which they grow.
Citrus trees can be grown in cooler climates if they are planted in containers and moved either into a home or greenhouse to protect them from cold weather. Dwarf citrus trees are the best option for containers because they require little or no pruning to stay an appropriate size for containers.
Determining When to Mulch
Mulching around citrus trees is often not recommended because of the potential for foot rot disease, which is caused by a fungus in soil that is too wet. In regions where dense, poorly drained soil is problem, such as south Texas or areas in Florida, mulching around citrus can cause more harm than good.
In drier climates where drought is a problem and irrigation must be limited, mulching around citrus trees can be beneficial. In Arizona, for example, mulching is advised to help conserve water. Mulch maintains soil moisture around the roots, where trees need it most, by limiting evaporation in hot, dry climates. Add a 4-inch-thick layer of mulch around citrus trees to keep soil temperature down, allowing healthy root growth to continue. Mulch also prevent the growth of weeds and grass.
Growing Citrus Trees in Containers
In areas that experience frost, or in areas where citrus diseases are a problem, citrus trees can be grown in containers. Select a very large container, no smaller than 2 feet in diameter, for each tree, and fill each container with a soil mixture specially formulated for citrus; the soil formula is available at many garden centers. The special soil formula is light and sandy, preventing moisture from accumulating around the roots and leading to rot.
In hot climates, container trees' soil must be watered twice each day. Mulching the surface of the container around each tree helps to prevent evaporation. Straw and wood chip mulches are options. Because containers' soil dries out so much more quickly than soil in the ground, mulch can be placed closer to the trunk of a tree in a container without causing rot. Ensure mulch is not closer than 4 inches to a container tree's trunk.
Mulching Around Citrus Trees
- Mulch should never contact tree trunks. Keep the mulch at least 1-foot from the trunk of a tree planted in the ground.
- Use high-quality mulch that allows for good drainage around each tree. Pine needles, straw and wood chips are mulch options.
- Avoid using mulches that absorb and hold water, such as sawdust, which can lead to rot.
- Never use hay to mulch around trees because hay contains seeds.
- Do not use inorganic mulches that do not decompose, such as gravel or rubber, around trees because they can cause the soil to retain too much moisture.