How to Kill a Christmas Cactus

Select products containing picloram for effectively killing Christmas cactus, as recommended by the Texas A&M University Extension. You can use the herbicide at any time of the year.

Fix a small garden sprayer with a 3-gallon tank and fitted with a coarse spray nozzle to will administer large drops of herbicide.

Fill the tank with water and add 4 oz. of herbicide to water. Mix in 1 oz. of liquid dishwashing detergent. This will act as a surfactant that will help the chemical stick to the cactus.

Mix in 1 to 2 oz. of blue dye to the herbicide mixture. Though this is not necessary, it will help you to identify the plant areas that you have already treated and make it easier to determine if you have used herbicide equally on all areas.

Spray plants and make sure you cover all the cactus branches or pads on the front and back. Avoid treating wet or moist plants. Do not use during extremely cold weather. Do not drench plants to the point of runoff.

Avoid the use of herbicide on windy days, as this will cause the chemical to drift to non-target landscape areas. Also, do not use picloram within 100 feet of land fractures or sinkholes, as this can lead to serious groundwater contamination.

Dig out and remove dead plants entirely, including roots.