Question
Hello John,
I found your wonderful section within the allexperts web site. I have an
invasive plant that grows all over our sideyard and on the backyard slope that
I can't seem to get rid of! It has barbs on it which makes it even more
annoying! :-) Hopefully you can see the barbs found on the stem within the
image.

I've attached a couple images in the hopes that you will be able to identify it -
maybe then I can find a way to eliminate it from my garden. (The second
image is how it is currently growing on our slope)

Thank you so much in advance for your time, expertise and any help you can
provide.

Kind Regards,
Diana

Answer
Diana,

What you have there is the common Asparagus sprengeri.  It is used all over the US as a very easy to grow ornamental plant.  We use it here in NW Louisiana in planters, pots, and hanging baskets.  It is only marginally hardy outside here in the winter time.  You must be in a fairly frost free location.  It has a very extensive root system which is probably why it was planted on your slope to prevent erosion.  To get rid of it is going to take repeated applications of RoundUp herbicide.  Then the roots are going to be a bugger to dig out after you kill it.

Good Luck,

John