How can I get rid of yucca plants?
Once a yucca plant has grown to a large size it is difficult to remove it completely. This is because yuccas grow very rapidly and have a very extensive root system. With persistence though a yucca plant can be eliminated. There are a number of ways to try:
1. By digging the plant up manually. First cut down the trunk to ground level, then using a spade remove the root system. Start at the perimeter and try to leave the root ball as intact as possible. Dig down about 4 - 5 feet. After the root ball has been removed, dig around the hole with a trowel or hoe and remove any pieces of root that have been left behind. Fill in the hole with new soil. It is very likely new shoots will eventually appear. These should be dug up as they appear and eventually you will be yucca-free.
2. By suffocating the plant. Begin by cutting the truck down to ground level. Place a layer of thick cardboard or 5 - 6 layers of newspaper over the entire area around the plant where roots grow. On top of this, place a thick layer of compost. Alternatively, the area can be covered with a sheet of thick plastic which is weighted down to keep it in place. Leave the coverings in place for about a year.
3. By using herbicides. Again, cut the trunk down to as close to ground level as possible. Then apply liquid tree stump remover (available from most nurseries). If the trunk is very large, then holes can be drilled in the trunk and the herbicide squirted into the holes. The herbicide will be carried to the roots and eventually kill them. As mentioned in method 1, shoots may eventually grow up and these should be treated with a herbicide spray. Remember to observe the recommended safely precautions when using herbicides.
Courtesy of NYBG Plant Information