The genus Yucca (Yucca spp.) Includes about 40 species of low-maintenance, drought-tolerant plants with sword-shaped leaves and panicles of flowers that appear on tall spikes. Most of the yucca species are short, shrubby plants, but there are a few tree types which feature the same sword-shaped leaves. Yuccas are extremely tough plants which could prove difficult to eliminate. They’re known to invade pastureland where they prevent grass from growing, but one plants may yield because of the rhizomous roots. Herbicide application and digging are best to fully eradicate the yucca issue.
Treat the yucca plant about two weeks before flowers bloom, throughout the booming period or within fourteen days after flowers perish for best results. Spray the leaves when they’re completely dry so the herbicide is not washed off the plant.
Prepare a 15-percent herbicide solution at a garden sprayer, using an herbicide containing glyphosate or triclopyr as the active component. Mix the herbicide with a surfactant like diesel fuel or vegetable oil, using 85-percent surfactant and 15-percent herbicide. A 1-gallon garden sprayer requires 19 ounces of herbicide.
Add 1 ounce of blue spray-marking dye to the herbicide solution in order that the yucca leaves are painted blue after spraying. This is especially useful when treating large stands of yucca to ensure you know which plants have already been sprayed. Alternatively, you can keep a bright-colored spray paint on hand and spray on the leaves of each plant after applying the herbicide.
Hold the spray nozzle above the middle of each yucca whorl — the across cluster of yucca leaves — and spray for about two seconds. Repeat with each whorl within a yucca cluster. A yucca plant may only have one whorl of leaves, but can have several separate whorls. If the yucca plant includes a fleshy trunk, spray on the trunk with the solution as well, in a procedure known as basal bark application.
Allow about one week to get the herbicide to take effect; the leaves will slowly turn brown to indicate the plant is dead. Treat the yucca a second time if no change is noticed after seven to 10 days.
Dig up the yucca root to ensure that the plant cannot grow back. Dig a wide circle around the plant to ensure you pull up all of the root. Sort through the soil after removing the most significant portion of the origin so it’s possible to remove any smaller, broken pieces of the rhizome. This takes lots of work and might not be necessary. Use this as a last resort in case you have previously attempted to eliminate the yucca with herbicide and it climbed back within the next calendar year.