An ashen grey willow with pale leaved tendils obscuring it's gnarled trunk. Sitting in the mire of great swamps, rare even in it's natural environment. The Banshee Willow's bark is known to have magical properties. Travelers beware, these trees seem to attract ghosts and other unsavory undead.
Demontrumpets, as illuded to by the name, are not normal plants, but are plants who hold their origin in the Abyss. Perhaps brought by summoned demons, perhaps created by a dark god for some purpose, perhaps simple plants mutated by an artifact of great evil.
A large, ruby-red pepper, found in dry regions; much prized by alchemists and gourmands alike.
As the PCs travel the road, right after a bend they hear a sharp whistle and call: "Heeey, not so lazy, move your asses!" It is a large man that calls, and there are unwilling workers that listen. A small company, 10-15 men work on the road, push boulders aside, dig up roots from under the road, etc. The large man that shouted turns to you, smiles fast and mutters something under his breath, sounds like cursing some lazy worker. "Where does the road bring you from, travellers?" And does a little small-talk.
And what is really happening? A group of bandits is 'adapting' the road for shady purposes. The road will not be wider, but tighter, with enough cover around (and a few traps perhaps), and will become an ideal spot for ambushing travellers or entire caravans. The bandit leader wants them all to appear harmless. The 'lazy worker' he cursed was actually a guard that should give warning before any travellers come around (fallen asleep). Not surprisingly, the boss may decide for an ambush even now.