I started to add a comment but didn't want to be misinterpreted. (Could happen.)
Let me just say that I agree with
@Weedwhacker that for a green plant in water with roots and no visible eggs or larvae (would they be visible?) you're best bet might be to use BTI.
A warning, tho, about BTI dunks. When they've been in water for awhile they tend to get all crumbly and would detract from the look of your plant and might muddy up (not right term but brain's on autopilot right now) the vase. Try to find the liquid form of BTI. If memory serves, and I think we all know by now that it might not, the liquid BTI is a clear liquid.
