Modifiers matching river:

• small,
• larger,
• sensitive,
• nearby,
• special,
• clear,
• major,
• perennial,
• large,
• fast,
• beautiful,

Simple categories matching perennial:

• flower,
• herb,
• weed,
• fruit,
• plant,
• grass,
• vegetable,
• seed,
• tree,
• shrub,
• allergen,
• forage,
• species,
• pasture,
• vine,
• native,
• pest,
• host,
• ornamental,
• veggie,
• crop,
• bunchgrass,
• river,
• group,
• antigen,
• planting,
• issue,
• legume,
• clover,
• wildflower,