What Is the Difference Between an Annual, a Perennial, and a Biennial?

All living creatures, including plants and flowers, have expected lifespans. Recognizing the differences between annuals, perennials, and biennials can help you determine the life expectancies of different garden center plants so you can choose the varieties that will work best in your garden, landscape, and containers.

Annuals

Annual plants are fairly straightforward. These plants complete their entire lifespan in just one year or growing season, from first sprouting from seeds and growing foliage, stems, and blooms to creating seeds to continue the next generation. After the plants die, they will not regrow from their initial roots, but must restart from seeds again as completely new plants. Annuals are generally faster growing and have longer bloom seasons, making them colorful showstoppers in the garden and landscape. Common and popular annuals include…

• Begonias
• Cosmos
• Impatiens
• Marigolds
• Petunias
• Zinnias

In addition to many popular flowers, most garden vegetables are also grown as annuals, though some of them would botanically be classified as perennials if they were allowed to remain in place for multiple years.

Perennials

Perennial plants are those with a lifespan that lasts at least three years, though they can live significantly longer as well. Perennial foliage may die back during the winter months but will regrow from dormant roots the next season. These plants often take longer to mature and may have shorter blossom times than annuals, but they can provide many years of beauty in the landscape. Familiar perennials include…

• Coneflowers
• Coral bells
• Daylilies
• Peonies
• Phlox
• Sedum

In addition to these elegant and popular flowers, hedges and trees are also perennials. These plants are staples in the yard and provide a foundation for any landscape.

Biennials

Biennials fall between annuals and perennials with a two-year life cycle. During their first year, these plants establish leaves, roots, and stems. Though they may die back slightly over the winter, they will rejuvenate in the spring and grow flowers in their second year, maturing to seeds before the plants die completely. Familiar biennial flowers include…

• Canterbury bells
• Columbine
• Dame’s rocket
• Forget-me-nots
• Foxglove
• Hollyhocks

Because these plants do not bloom in their first year, patience is essential to enjoy their beauty in their second year. Planting biennials in two successive years can ensure the plants enhance the landscape in multiple years.

Choosing Annuals, Perennials, and Biennials for Your Yard

Once you understand plant lifespans, you can more easily choose the plants that will give you a landscape you love. When choosing plants, larger perennials can create a stunning foundation or border for your yard, including showstopping specimen plants and shade trees. Smaller perennials can fill in larger spaces in flowerbeds and edging, while annuals add brilliant color to pathways, edges, and very visible spaces, including porch pots and containers. Biennials can be spectacular transition plants, particularly if you may plan on expanding your landscaping beds in the future, or want to fill in a space temporarily before adding a new deck, porch, or otherwise expanding your home or outdoor living space. Biennials are also great choices if you want to enjoy a changing landscape without as much work each year, because you can enjoy the plants for two years before they need replacing. Many biennials are self-seeding making them great additions to the cottage garden. Ultimately, a landscape that includes a thoughtful mix of annuals, perennials, and biennials will showcase different colors, textures, and growth patterns for stunning visual interest. New cultivars are developed every year, and greenhouses often have the latest plants and newest showstoppers on display. If you plan a mixed landscape, you will have the freedom to enjoy new plants as they are introduced and you will always have new plants to be excited about.

Caring for Annuals, Perennials, and Biennials

While the differences between annuals, perennials, and biennials may seem clear, different plants can have different lifespans based on the exact cultivar, gardening zone, climate variations, and even microclimates within an individual landscape. Furthermore, the care plants receive can ensure they reach their maximum potential for the longest, most productive life. Strader’s Garden Center experts can provide recommendations and guidance for the best plants based on your preferences and needs and assist you in choosing plants that will thrive in the conditions of your yard, including soil type, sunlight levels, fertilization, moisture levels, and other needs. To provide each type of plant the best care, consider…

• Annuals – Provide nourishing fertilizer formulated for the type of plant, and weed around them carefully so these fast-growing plants don’t need to compete for moisture and nutrition. Soaker or dripper hoses can also provide great watering as these plants flourish.
• Perennials – Be sure these plants have adequate space in the landscape to reach their full size. Good quality mulch can help protect the roots each winter so the plants remain healthy for the next spring.
• Biennials – Take care to provide appropriate fertilizer for these plants in their different life stages, and mulch around those with basal leaves to provide good winter protection during their dormancy.

Adding annuals, perennials, and biennials to your landscape will not only help you learn about plant lifespans, but you will enjoy a more varied and richly diverse landscape, with plants that provide beauty through the years.