noun
General term for plants that produce flowers; often used in botanical or horticultural contexts.
この温室には珍しい花卉がたくさんある。
There are many rare flowering plants in this greenhouse.
noun
ornamental plant
Emphasizes plants cultivated for decorative purposes, such as in gardens or floral arrangements.
公園には色とりどりの花卉が植えられている。
Colorful ornamental plants are planted in the park.
Compound of 花 (flower) and 卉 (grass/plant). The character 卉 is rare in modern Japanese and is often replaced by kana.