Modifiers matching clover:

• perennial,
• wild,
• annual,

Simple categories matching perennial:

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