The Season to Trim a Dwarf Mexican Lime

Light Trimming

• Keep your dwarf Mexican lime looking healthy with light pruning at any time of the year. Light pruning includes removing any growths below the graft, which is where the bark changes texture or appearance. These growths below the graft will be thorny suckers that draw nutrients from the rest of the tree and do not produce edible fruit. Remove any vertically growing water sprouts above the graft during light pruning to prevent these thin, thorny branches from blocking sunlight to the center of the tree. Not all thorny branches growing on your Mexican lime tree will be water sprouts or rootstock suckers, especially if you have a thorny variety of Mexican lime. Correctly identify suckers and water sprouts to remove by their growth habits rather than the presence of thorns.

Heavy Pruning

• Unlike deciduous trees, citrus trees like dwarf Mexican limes, also known as Key limes, do not require extensive pruning. The only heavy pruning you will have to do is if the tree has a lot of deadwood on it or if a significant portion was killed during a winter freeze. The best time to remove anything damaged from a freeze is the following spring, after there is no chance for a frost and you can see new growth on the living portions of the tree. You may need to wait until May to do this type of pruning for your tree. If your area rarely experiences freezes in the winter, you can prune your dwarf lime in the late winter to get rid of crossing or touching limbs and deadwood, but if your lime tree could be exposed to a freeze, wait until the early spring to do any pruning. Avoiding freeze damage is especially important with dwarf Mexican limes, as their wood will be damaged by temperatures below 29 degrees Fahrenheit, according to the University of Florida's IFAS Extension.

Age of Tree and Shaping

• The age of the tree does make a difference when pruning. Citrus trees, in general, do not require anything except deadwood, water sprout and sucker removal for the first 15 to 20 years. If you want your lime tree to maintain a particular shape, prune a lime tree of any age lightly twice a year. When pruning to maintain a particular size and shape, cut off those branches that grow above the desired 6- to 8-foot height.

Pruning Practices

• Whether lightly trimming your lime tree or removing extensive freeze damage, there are some things you need to do every time you pull out your pruning shears. You should always disinfect the shears before and after you cut, especially if you are cutting off diseased or dead branches. Mix equal parts of bleach and water to make the disinfectant solution. To lengthen the life of your pruning tools and prevent corrosion, wipe the shears down with a cloth covered in mineral oil after you finish pruning. Small water sprouts and suckers can be pulled off with your hands. Larger branches and deadwood should be removed with shears so the cut is flush with the branch collar, which prevents damage to the trunk or larger limb the removed branch was attached to. If you live in a desert area, with extremely heavy sun, you should protect your dwarf Mexican lime tree's trunk from sunburn where it is not shaded by the canopy branches with a coating of whitewash or white latex paint mixed with an equal amount of water.