The term 'small plant' can be summarized by two crossword solutions: Bonsai (6 letters) and TREFOIL (7 letters). Bonsai is a type of tree or shrub that is cultivated to remain small through pruning and shaping. It is an art form originating in Japan and is often used as a decorative element in gardens. TREFOIL is a type of clover with three leaflets. It is a low-growing plant that is often used as a ground cover in landscaping.