Thursday, October 8, 2009


This is Yucca filamentosa, a non-native plant commonly seen in landscaping. Yucca was often carried by settlers and planted near the homestead

Apparently, by breaking the tip off the leaf and pulling away the attached filaments, you could use it as a crude needle and thread for mending clothing. The filaments are usually seen unraveling from the leaf margin.

Yuccas are attractive plants. Stands like this remind me of Florida. This is a very hardy plant that can survive some pretty severe growing conditions

The long waxy leaves funnel rain water in towards the base of the plant. This concentrates the water from a large area right to the root system. This also causes a corresponding dry zone that reduces competition from other plants trying to grow around the base of the Yucca. Besides robbing the surrounding area of moisture, the thick bunch of leaves almost eliminates sunlight penetration.

The Yuccas are beginning to move out of their grove of trees and spread through some of the prairies. I figured the seeds would move down hill into the dense cedars where the seedlings would die for lack of sunlight. These plants are moving up a steep slope and it’s time for me to put a halt to their progress. My next five year management plan will definitely have a section on Yucca control.

I’ll have to do some trials to discover the most effective control technique for Yuccas. A normal concentration of glyphosate is not terribly effective in killing this plant because of the difficulty in getting good coverage on all of the leaves. Even with a surfactant to break up the wax coating in the leaf, the herbicide tries to bead up and roll off the plant. Trying to get total spray coverage also results in a lot of dead nontarget plants in the vicinity of the Yucca.

One technique I’ll try is the application of a higher concentration of herbicide to the center of the leaf whorl in the spring. The rapidly growing leaves may take in enough herbicide for an effective kill.

After a couple of years the dead leaves of the Yucca create a thick mulch around the base of the plant. This is another way that this plant conserves moisture for itself and discourages other plants from germinating. Another control method I’ll try is cutting the Yucca off at the base and applying herbicide to the stump. Without the herbicide, the Yucca would send up new shoots and continue to grow.

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