How do you survive in a world with dragons?
The answer is, most don't survive a nightshade; while there are some who could band together and struggle against a nightwing, nightwalkers are terrific threats that carve swaths of devastation when active. As for nightcrawlers, they are the source of the Darklands, the regions of the plane that have the minor negative-dominant trait. These are the lairs of the great beasts.
Fortunately for indigenous life, being a native of Shadow confers some limited protection from the notice of nightshades and shadows, for your own physiology incorporates some of the same darkness that makes up theirs. Thus, unless you're right in their path or associating with someone or something from a more lighted realm, or they're feeling particularly aggressive, nightshades aren't likely to go out of their way to assault you. That said, the more concentrated life is and the more structured the shadowstuff nearby, the more likely it is that a nightshade will strike.
Shadow flora does not derive life from solar illumination. It flourishes under different conditions.