Looks like your Carissa is showing its cornuta DNA. You could call it reverting to its original phenotype. That would be my guess.

how did you happen to spray so wildly that you got RU on your holly???

try extremely low pressure ... and tip adjustment.. to create droplets .. that gravity makes fall to the ground.. instead of atomizing such.. so it drifts in the wind ...

i know nothing about holly.. can we rule out grafting and understock issues???

are you spraying suckers with RU????

ken

Thank you, rhizo! That's perfect.

I Googled just now and found a good example. Look a the first photo in this link:

"This picture shows how one Asian cultivar that initially has smooth-edged, oval leaves can soon revert back to its original form with very angular, pointy leaves."

http://www.clippinvasives.org/chinese-holly-ilex-cornuta-japanese-holly-ilex-crenata-and-various-cultivars/

Ken, the bushes are very resilient and can handle losing some growth to Roundup. The ugly pointed growth is very much mixed together with the regular growth, so it wasn't possible to be perfectly selective. Also, I didn't mind if I killed the bushes because if I couldn't kill off the ugly growth then I was planning to rip out the bushes entirely.