[Pwnguinz]

Plants don't just "reproduce themselves". Nor do they "infect" other plants. This is not a "infectious" trait. If you cross pollinate (a.k.a. 'breeding plants'), the active genes responsible for glowing in the dark may or may not even be passed down.

Though your concerns are well noted--see Monsanto's 'terminator' crops cross pollinating with neighboring 'normal' crops and making their seeds also sterile.