Yuccas - dividing them

I am fairly new on here and I have found some very informative info here but I want to ask about yuccas. My daughter-in law gave me 3 starts of it and I brought it home and stuck it in one of my small flower beds. That was 12 years ago. This year I decided I wanted to move it cause it was taking over everything in that bed so my husband and I started digging it out. WOW WHAT A JOB !!!!!!!!. the root system on those dudes was as big as a small sappling and they have grown up under our trailer. We managed to get the yucca out but we had to leave the main root as it was way down deep and to big to pull out. Now does any one know how I can get rid of the main roots left in the ground. By the way out of those 3 plants I got 20 new ones. Go figure. If I had known they would be that way I would have put them else where.

Can you get to the tops of the roots left in the ground, or are they too deep? If you can get to them, and they are over 3/4 inch or so in diameter, you can drill a hole straight down into the roots right in the center and pour full-strength RoundUp (glyphosate) in the holes. It will migrate on down into the roots and kill them. The temps need to be near 70 degrees for the glyphosate to work, though. IT WILL NOT CONTAMINATE THE SOIL. You may have to do this more than once. Salt is not recommended because it will stay in the soil and you don't want to pollute your yard.

ok I have other plants in there and this won't kill them? they are bulbs and such.

As long as you don't splash any on your other plants they'll be fine--depending on how crowded the bed is that can be tricky sometimes, but if you're careful then you won't have any problems.

Don't think you can just pour some Roundup where the roots are. It has to come in contact with live plant tissue. Unless the live roots are exposed, and you can use a drill and make a hole down INSIDE the root, this won't be of any benefit. As ecrane says, the product shouldn't touch any of your other plants in the same bed. Yucca roots can be very persistent, and this is the most efficient way to "kill them dead."

Or take my Hubby's Lazy Man Method: Dig up what you can and every Saturday for the rest of your life, pour a 1/2 cup of Round UP and with a foam paint brush, paint the little baby buggers.

If your yucca roots do send up sprouts, nanbernier is exactly right. If you paint the sprouts with Roundup and keep at it, eventually all the roots will be killed. The reason you paint it on is to keep from accidentally having it get on plants you want to protect.

I'm even lazier, just pour weed killer into the cap off the bottle and pour it directly on a fresh cut. Wear gloves. Worked for my big privet.

Worked on PRIVET!!! Wow! Thanks for that!!!

Thanks for the help. Of couse now I will have to wait til warm weather again to try this. Hopefully I can get it done this spring. I have enough Yuccas for the world I think LOL There is one piece of the root showing so shouldn't have any problem.