January 20, 2018
I have some yucca plants that are about 8 or 9 years old. I took them out of pile of dirt, rocks, and trash pushed up with a dozer preparing ground for our house and yard. Some are tall enough that they’re beginning to fall over. Should I cut them back? If so, in what season? How short? How long will it take them to produce blooms after they are cut back? Blooms are attacked by some insect each year. They destroy the blooms pretty quickly. One year I succeeded in avoiding most by spraying an insecticide when I noticed small black bugs. One of the attached pictures is my attempt to photograph that bug. I think the little black bug is the problem. Earlier I thought a larger bug that swarms the blooms before they begin to die. County agent told me the larger bugs are assassin bugs and I should leave them alone—they’re my friends. Do you have any suggestions to protect the blooms?
Are they falling over because their roots aren’t established enough, or they are simply too top heavy. Pruning them back may set back their blooming for a year or two as new rosettes form and mature enough to bloom. Typically they multiply quite rapidly. The small black insect could be an aphid which can go after the blooms. They can easily be controlled with insecticidal soap. If you are going to cut them back, do so as new growth is beginning in the spring. We are having a really cold winter so far, and cutting them back now would expose them too much. If the insects come back again, collect a few in a small jar and take them into your local extension office for proper identification.
I dug up a yucca plant in my yard and thought I was done with it. Now I have noticed a lot of small yucca plants beginning to sprout. How do I keep these plants from coming back up? I do not want any more yuccas.
Yucca plants are tenacious and will re-sprout from any roots or crowns left in the ground. You can try digging up more of the plants and try to get as much of the underground portions as possible. Then be diligent in cutting them out as you see new sprouts. Spot spraying them with a Round-up product or a brush killer can also help, but you still need to monitor the area for a few years to make sure you have no surprise visitors.
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