The word "beginning buds" describes the early stages of growth of a plant or flower. To express the opposite of "beginning buds," we may use antonyms such as "mature blooms" or "fully blossomed." These words refer to the period when a plant or flower has achieved its maximum growth and beauty. Other antonyms for "beginning buds" may include words such as "wilted," "dried up," or "decayed," which indicate that a plant or flower has reached the end of its life cycle. Alternatively, we can use the word "budless" to describe a plant or flower that has not yet produced any buds or shoots.