I've not played a Plant/ but I've been reading a bit about them with a view to play one.
As it's not perm I would go 3 recharge and then split the others to get the desired effect for me 1 acc 2 dmg.
On a side note an effective way to level a Plant/ seems to be to use SoC on a mob so that they attack each other and then spam Roots on them, the mobs will go down quickly and you will get most of the xp.
SoC recharges relatively quickly so will be available for most mobs.
L50s: Tanks: Cryofission - Ice/EM - Dr Celsius - Fire/Ice - Saint George - SD/SS | Controllers: Psichosis - Ill/Kin - Major Chaos - Ill/Stm | Scrappers - Neutron Crusader - DM/SR
Currently Levelling: Angelic Blade - BS/WP Scrapper | Seeds of Destruction - Plant/Kin Controller
A reminder about confusion tho, you need to apply confusion twice for bosses if you don't get overpower.
Psiphon's advice is what i use with Psy-knight. Of course as a Mind Controller he can confuse one mob at a time. Then locks down mobs and finishes them off.
Also there are many good confusion invention sets with sweet bonuses.
I can't give any advice for Creepers tho, as i never ventured in Dominators and my only Plant troller lived barely to see Coyote i have no idea about Plant controllers powers.
ive got the purple set waiting for me so no problem there...
not to sure what to slot carrion yet im goin towards 2 rech 2 acc 2 dam at 50
Any ideas? i have tactics so acc shouldnt be to much of a problem.
oh and im plant/storm so going to be using carrion, tornado and lightning storm as my main damage attacks.