This topic gets brought up at least once a year.
https://www.project1999.com/forums/search.php
Anyways,. as a shaman use root all the way up till you get paralyze earth.
enstill is a waste of mana, great way to get yourself killed.
immobilize is okay mainly because it's low cast time, but that's about it.
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Mobs break root like crazy when you're sub 60 and even very often when you are 60. Malo line of spells will help with root breaks due to -MR. But you honestly want to use your cheapest root because of root breaks. P99 is coded to be difficult. Root Break is checked on server ticks, every 6 seconds.
You could land root 1ms before the server tick and have it break instantly.