I don't know. Maybe they do too much. I just leave them alone and let them grow. Water them when they need it and give them minimal amounts of food. Many people overfeed which is why they have issues.
I did go to move this one only to find out a big root had grown out of the bottom of the pot and into the ground. It's just an Ethiopian I didn't have room for indoors so I just put it in the backyard and watered it when it was dry. Doesn't look all that good and I still don't know what to do with it. It hasn't even started flowering yet. I hate killing plants but this one might just have to go as it can't come inside and it definitely won't finish even in the greenhouse. It's a sativa that takes about 14 weeks to flower. The tops had just been supercropped. It's quite pale and obviously underfed but it's just been fed with the hose and maybe 2 light feedings. It's been neglected but still growing pretty healthy considering everything.