plant/storm question

Roots has a -knockback that lasts for only 12 seconds (which cannot be enhanced) . . . but it also has a 20% accuracy penalty (like most AoE controls). With a single accuracy, you will be missing a lot of foes in the groups you try to Immobilize with Roots. That is most likely the reason you are seeing foes fly all over the place -- they weren't locked down with Roots. To use the lockdown trick, you have to keep firing off Roots every 12 seconds, and it has to hit.

Roots is a power that really needs IO slotting to maximize the benefit. Ideally, you have several sets that provide some Global Accuracy buff and some sets that provide Recovery buffs, and then you can slot the Posi-Blast set in it. If you are just trying to get by with Frankenslotting, try to get at least 60% or more Accuracy, capped or nearly capped damage and then as much Rech and EndRdx as you can . . . don't worry about Immob since Roots will re-cast much faster than its unenhanced Immob duration.

Even with better accuracy, Tornado will still toss around foes some. AoE control powers will usually miss a few, and that's something you just have to live with if you want to use Tornado as a damage power. For the most part, I save Tornado for situational use, but it is great for those situations. Against tough targets or targets with high Defense (like Paragon Protectors who hit MOG), the autohit Damage over time is great. It is also a great "panic button" power for when things get out of hand and you have too many foes coming after you -- the chaos is quite welcome to spread out the group so that you can catch a moment to heal or recharge.

One option if you want to use Tornado against single targets is to use Entangle. It has a 15 second -Knockback and higher inherent accuracy.

Yes, I am aware of the knockback one-star club. I thought I had read somewhere that the -kb of roots was useful against tornado which is why I asked. I wouldn't use tornado against mobs when on a team unless we were about to get wiped.

You probably have better accuracy than a single SO in the power. It works fine, but you need enough accuracy to overcome the 20% accuracy penalty built in to Roots.

To the OP, you need to add more accuracy. Roots needs a minimum of 2 SO's worth of Acc. Standard SO slotting would be 2 Acc, 2 Dam, 2 Rech, but IOs let you do better than that including adding in some EndRdx. Immob really isn't needed since you'll be re-casting long before the original Immob runs out.