I'm running a campaign that has a handful of slightly altered creatures (so far the main includes are Swamp Orcs, Swamp Basilisks, and rumours of the Titanic Cave Mimic), and was looking for a bit of help in making a Corrupted Dryad.

The flavours behind it that I have so far is that she is attached to a sickly tree in a swamp. An area approximate to a normal Dryad's territory (something like 300meters radius from her tree iirc) has a notably increased amounts of decay, rot, smells, slimey algae laced rocks, etc.

I'm not sure if it's a better story if the reason the land is nastier is because of her, or if the reason why she is corrupted has something more to do with her land/tree. (Meaning if the PCs can fix the land a bit by taking her out of the equation, or if they can do a non violent intervention that would "cure" her)

One thing that I am going to introduce to the campaign will be a Gulthias Tree, which I guess could possibly use a Corrupted Dryad somehow... I just need to bounce a few ideas around to get something I like.

I'm looking at the Dryad's stats too: http://www.orcpub.com/dungeons-and-dragons/5th-edition/monsters/dryad

Would you change anything in there? I'm OK with increasing the creature's CR a notch if she gains some moderately powerful offensive spells.