Best viewed with some eerie background music.

Had the same problem with jumpers when I kept adding mulch and manure. Got to have a fair amount of barrier above the ground plus it needs to curve inward as I recall to deflect the rhizomes back. I used a roofing material used on commercial roofs (can't recall the name of it). Very tough stuff - no roots under or thru it. Rgds

Thuja, yes, pretty scarey. I beat the heck out of it with a shovel before getting close enough to remove it. Didn't want to take any chances.

Fredgpops, I am beginning to think that possibly some rhizomes have gone under the barrier also. I only had about 45 minutes yesterday to dig up the escapees, but found that the closer I dug back toward the barrier, the deeper the rhizomes were. One small emerging clump of Henon next to some banana plants, and about eight feet from the Henon barrier, had a rhizome that went straight down from the plant. I thought I could pull it up back toward the barrier, but it went straight down. It broke off about 14 inches below the surface.

Also, I am now thinking twice about digging around the outside of the entire barrier. Where the barrier hasn't failed(yet), it is bulging outward, and my thinking is that if I remove the outside soil, it won't have anything against it for resistance to keep from busting out. If it has soil up against it, it will be less likely to push outward and break through.

Just my thoughts on the barriers.

Kt