Last week we had a low-HD, conveniently humanoid, relatively unproblematic monster with an universally agreed-upon LA? Time for a sessile plant that messes with the action economy.
Udoroots are Huge-sized subterranean bulbs, whose six crowns can sense other creatures with blindsight and manifest psychic powers. The crowns don't share the root's HP pool, and instead are sunderable objects with 7 HP and hardness 5.
Like all plants, they're immune to electricity and resistant to fire and ice. They also have some natural armor and small bonuses to constitution, wisdom, and charisma (in addition to a -6 intelligence penalty).
The first problem: as mentioned above udoroots can't move. I guess one could be transported by an ox cart, or put on a few mid-level floating disks, or given movement through some obscure template, but even then its mobility is going to be very limited compared to other characters.
Udoroots have a number of psionic powers, of which the most notable ones are probably at-will False Sensory Input, at-will Mind Thrust, at-will Telekinetic Force, and 3/day Astral Construct. As long as at least two of the six crowns remain, the udoroot can use two PLAs a round.
While the concept of a giant psychic plant is cool, and two PLAs a turn are some serious firepower, the udoroot is simply too reliant on its frail crowns to actually do anything. A few sunder attempts, or an area attack or two, and the party is down a team member.
There's also the issues of poor object manipulation, terrible mobility, and difficulty using magic items. Considering all of those, the udoroot deserves -0 LA. I could slap on an asterisk for the inability to move, but that's not game-breaking as much as just really annoying.