Getting rid of agapanthus roots!

I have removed a large area of overgrown agapanthus in my front yard; they were probably originally planted 20 years ago. They were taking over the yard and seemed to only have value as real estate for a LOT of snails. A LOT. TOO MANY SNAILS! It is a semi-shady area that I am going to use for a variety of other plants.

Given the age of the agapanthus, the root system is long, deep and tough to get rid of (some roots are as big around as large grapefruit). I've dug out as many as I can on my own, and can't afford to rent equipment to do more. I'll probably need to add some soil to the area before planting.

I don't have much money for any of this, but wondered if anyone has suggestions or input. Any way to kill/remove more roots? How much of a problem will remaining roots cause for new plants? What is the best inexpensive, viable soil (about 2-3 inches deep), and will it have to be tilled deeply before planting?

Thanks!
Val

Val, do you still have any of these? I would gladly pay for the shipping to send them here.Even if they've been out of the ground for a couple of days. PLMK

Sorry I don't have any advice for you other than roundup.

Steph

Sorry Steph - I got rid of them already.

Thanks :)