Can I ask why? Just for debate? Would like to see some different plants added to the gardening list. But reg plants? If you can get them added in, why not. But until then play the game and take advantage of how regs are distributed now. How about some quests where you are rewarded with regs, kind of like the solen powder quests since those are pretty much worthless now.
Use green thorns that you can grow. Or did they change using a green thorn to not spawn regs? Never used green thorns, though I know someone that does.
Since the lrc/lmc introductions, I rarely need regs anymore. And when I do, say for scroll/potion making (I try to keep 5k of each on hand), I have a cat statue that I empty everyday. I seen keeps/castles with 10+ statues
Plus depending on what I am hunting I take regs from monster kills when I know that I am getting low. Heck hunt juka mages you get some of every reg except necro ones.
Also since I fish up treasure chests, I save the regs from them. You can actually get quite a few regs from just normal gameplay, it is just that most people do not/will not take advantage of the regs as they are now.