Prickly pear is a native desert cactus growing extensively in the southwest regions of the United States. However, the plant spreads rapidly and is among the hard-to-control species, often interfering seriously with livestock feeding. Prickly pear is highly tolerant of herbicides and mowing only spreads the plants. The cactus commonly occurs in waste areas and over-grazed pastures. You can get rid of the plant in any one of several ways.
Things You'll Need
Small pump-up garden sprayer
Liquid dishwasher detergent
Shovel or grubbing hoe
Mix 4 oz. of herbicide with 3 gallons of water to prepare spray. Add 1 oz. of liquid detergent to the mixture; this helps the herbicides to coat the waxy pads of the cacti more thoroughly. Mix in 1 to 2 oz. of blue dye to help you to keep a tab on treated areas.
Fill the garden spray with the solution and attach a nozzle that will deliver a coarse spray in the form of large droplets as opposed to a light sprinkling.
Start spraying on the plants making sure to cover all pads and stems until the plant is wet without any runoff. Spray herbicide on both sides of the pads for best results. The plant will die very gradually following foliar applications. The entire plant may take up to two to three years to die.
Use the top-removal method of getting rid of prickly pear as an alternative to herbicide use. This involves cutting the main root of the plant 2 to 4 inches below ground surface using a shovel or grubbing hoe.
Stack detached plants on brush piles until you discard these. Avoid pad contact with soil as these will root and create new plants.
You can use herbicide any time of the year except during cold weather and in low temperatures. Do not spray on wet plants as this reduces efficacy of the chemical.
Do not treat prickly pear with herbicides if plants are growing under desirable trees such as oak or pecan; the chemicals can harm trees. Avoid herbicide use within 20 yards of endangered plant sites.