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A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter-lived annuals and biennials.
Definitions. Annuals are plants with a life cycle that completes within one growing season, typically less than one year, and ending with fall's first frost. Conversely, perennials complete multiple life cycles over many years.Common garden marigolds are annuals, but because they self-sow, sometimes they are mistakenly identified as perennials. Even in regions with mild winters free of frost, marigolds grow as annuals, with bloom development fading in fall.Of the perennial marigolds, you're only likely to find three species available.efinitions. Annuals are plants with a life cycle that completes within one growing season, typically less than one year, and ending with fall's first frost. Conversely, perennials complete multiple life cycles over many years.