Three nitpicks first:
1) Needs tone editing, typo correction, and binomial formatting.
2) Referring to Typha latifolia as a bulrush confused me til I looked it up: Americans know that plant as the common cattail. Just a note. (Likewise, that's one plug-ugly cattail head, heh.)
3) Why wasn't it classified as Keter in the first place? The references to a K-class scenario are right there in the body of the article. Asking for an upgrade frankly just reads like you shoehorning in your character.
Okay, on to the substance of the article…
Invasive cattails exist. Typha x glauca, a hybrid of the two native North American species, is merrily on its way to wrecking half our wetlands. (It doesn't explode, of course…) While I do think that the concept of SCP-level species invasiveness, especially as a K-class scenario, has potential, I don't think this fulfills it. It doesn't have enough of a hook.
Also, a plant that produces no oxygen is about as normal as a human that produces no urine. That's worth more than a tossed-off reference at the very end.
