By Heather Kirk-Ballard

LSU AgCenter Horticulturist

Living in Louisiana has many advantages, including our subtropical climate that supports the growth of many different types of plants that require warm, humid temperatures. This include citrus trees, which are native to subtropical and tropical climates and are winter hardy in USDA plant hardiness zones 9a through 11. Louisiana USDA hardiness zones cover 8a through 10a.

In the southern part of the state — especially along the coast and in St. Bernard and Plaquemines parishes — citrus trees thrive outdoors with few problems when it comes to temperatures. However, citrus diseases have devastated the commercial industry. In central and northern Louisiana, which are in zones 8a and 8b, citrus must be grown in a greenhouse or brought indoors during cold months when there is a threat of frost. Growing citrus in containers can help with this.

Cold-hardy citrus such as satsuma, sweet oranges, grapefruit and kumquats can grow well outdoors in Louisiana. Less cold-hardy types such as lemons and limes can survive when protected during hard freezes outdoors once they are older, larger and established. Many home gardeners have lost more tender trees in extended freezes.

Some recommended citrus for containers are Improved Meyer lemon, Bearss lime and kumquats. These are naturally smaller trees that will last longer in containers.

One benefit of growing citrus in containers is being able to bring the plants indoors during extended freezing temperatures. Standard citrus is too big for indoors, but dwarf varieties grafted onto rootstocks that limit their size help make them easier to grow in containers and speed up the fruiting process.

Container size and material type is one of the most important factors for success of container-grown citrus. If you buy a 5-gallon-size plant and want to bump up the size, don’t go too large. A 5-gallon pot is 12 inches in diameter. You want to double that size to 24 inches for the next container and allow for growth of roots as well as the tree.

Light-colored plastic pots on wheels with drainage holes make great selections because they are lightweight, and the lighter colors do not heat up as much in the summertime. In addition, the wheels make moving the plant indoors in freezing temperatures much easier. Lightweight resin and fiberglass planters are an excellent choice, but good old-fashioned terra cotta and ceramic are beautiful. You may want to place them on plant dollies for easier movement because they are heavier.

Citrus are active year-round. They do not go dormant in wintertime but do slow their growth. Most citrus will go into active growth in late winter and early spring, followed by flower production that gives way to fruit in the fall and winter.

For the best fruit production, place in an area that gets six to eight hours of direct sunlight. Make sure the pots stay evenly watered. Use a potting mix that has both good water retention and drains well such as a lightweight potting mix with inorganic ingredients such as perlite, vermiculite, coconut coir and peat moss.

Citrus benefits from annual fertilizing that increases with each year of age. Young trees should be fertilized with light but frequent doses of 10-5-5 fertilizer or one specific for citrus throughout the growing season from spring to early fall. Apply fertilizer in a 3-foot-diameter circle around the tree directly under the tree canopy by spreading. Do not mound fertilizer around the trunk. Stop applying in late fall and winter.

Limit the size of your trees and promote bigger fruit by pruning after they have produced and you have harvested. Be sure to remove rootstock suckers that have thorns with pruners. Most importantly, protect citrus in freezing temperatures by moving them inside until the danger of frost passes.

Citrus offers interest year-round with evergreen foliage, highly fragrant flowers and, best of all, tasty, nutritious fruit that can be picked from the comfort of your home patio.

Citrus can be grown year-round in containers and pulled indoors to be protected against low temperatures. Photo by Heather Kirk-Ballard/LSU AgCenter

Satsuma varieties grafted onto dwarf rootstocks can be successfully grown in containers year-round and protected in the winter. Photo by Heather Kirk-Ballard/LSU AgCenter

Citrus trees such as Improved Meyer lemon on dwarf rootstocks grow well in containers. Photo by Heather Kirk-Ballard/LSU AgCenter

Gorgeous satsuma fruit ready to be eaten. Photo by Heather Kirk-Ballard/LSU AgCenter