12 Difference Between Perennial, Biennial And Annual Plants

What are perennial plants?

Perennial, any plant that persists for several years, usually with new herbaceous growth from a part that survives from season to season. Trees and shrubs are perennial, as are some herbaceous flowers and vegetative ground covers. Perennials have only a limited flowering period, but, with maintenance throughout the growing season, they provide a leafy presence and shape to the garden landscape. 

Popular flowering perennials include:

Types of Perennial Plants

There are generally five types of perennials. They include: harbaceous, woody, monocarpic, deciduous and evergreen.

  • Herbaceous perennials are typically grasses that grow in fire-prone areas and on prairies.
  • Woody perennials are found all over the world and include vines, shrubs, and large towering trees that take years to grow completely.
  • Monocarpic perennials are plants that flower and make seeds, then die. They are perennials because it takes them more than one year to complete this process.
  • Deciduous perennials are plants that shed their leaves in the fall of the year.
  • Evergreen perennials are those plants that live long lives and keep their foliage during the fall and winter months.

What are annual plants?

An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical location, and may not correspond to the four traditional seasonal divisions of the year. With respect to the traditional seasons, annual plants are generally categorized into summer annuals and winter annuals.

Summer annuals germinate during spring or early summer and mature by autumn of the same year. Winter annuals germinate during the autumn and mature during the spring or summer of the following calendar year. One seed-to-seed life cycle for an annual can occur in as little as a month in some species, though most last several months.

Examples of Annual plants include:

Types of Annuals

There are generally three group of annuals, they include:

  • Hardy or cool-season annuals, such as forget-me-not and larkspur, thrive in the cool to moderate temperatures of early spring and fall and can tolerate exposure to light frost without being protected.
  • Tender or warm-season annuals, such as marigolds and petunias, are native to tropical or subtropical climates and require heat to grow and thrive, often growing poorly during cold weather. To ensure their survival, it’s best to wait until late spring to add these plants to your garden beds or containers.
  • Half-hardy annuals are most common and fall in the middle-of-the-road. They tolerate a wide range of temperatures, including periods of cooler weather near the beginning or end of the gardening season.

What are Biennial plants?

biennial plant is a flowering plant that takes two years, generally in a temperate climate, to complete its biological life cycle. In the first year, the plant undergoes primary growth, in which its leaves, stems, and roots (vegetative structures) develop. Usually, the stem of the plant remains short and the leaves are low to the ground, forming a rosette. After the first year, the plant enters a period of dormancy for the colder months. Many biennials require a cold treatment, or vernalization, before they will flower. 

During the next spring or summer, the stem of the biennial plant elongates greatly, or “bolts”.The plant then flowers, producing fruits and seeds before it finally dies. There are far fewer biennials than either perennial plants or annual plants. Sugar beets and carrots are examples of biennials.

Difference between perennial and annual plants in tabular form

DescriptionPerennials are plants that live more than two years or more than one growing season.  An annual is a plant that lives only one year or season.  
LongevityPerennial plants re-grow every spring.  Annual plants live for one growing season.  
PlantingPerennials are normally planted in the autumn to produce spring blooming parts.  Annuals are usually planted during the spring.  
Life CyclePerennials usually come re-grows after a year from their own overwintering roots even though their foliage may die to the ground after frost.  After these plants complete their life cycle in one year, they must be started from seeds or cuttings.  
Bloom TimePerennials bloom from the spring or summer of the second year.  Annuals tend to have a relatively long bloom season.  
AppearancePerennials are usually less bright and showy.  Annuals are usually bright and showy.  
Death Of Plant StructureIn many perennial plants, it is only the top portion that dies annually.  The whole plant structure of annual plants dies annually.  
Reproductive StructureThe reproductive structure of perennial plants mostly produces seeds and bubils.  The reproductive structure of annual plants mostly produces seeds only.  
Growth, Formation Of Seeds & Transition To Flowers.Perennials are relatively slow in growth, transition to flowers and in formation of seeds when compared to annuals.  Rapid growth, rapid transition to flowers and rapid formation of seeds are also some of the major characteristic of annual plants.  
ExistencePerennials can survive many conditions including the harsh conditions.   Annuals only survive and grow effectively in favorable conditions.  

Key Points

  • Biennial Plants which require two years to complete their life cycle. First season growth results in a small rosette of leaves near the soil surface. During the second season’s growth stem elongation, flowering and seed formation occur followed by the entire plant’s death.
  • There are far fewer biennials than either perennial plants or annual plants.
  • This are plants that persist for many growing seasons. Generally the top portion of the plant dies back each winter and regrows the following spring from the same root system.
  • An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies.
  • Some annuals become perennials in warmer climates, when the lack of a hard frost allows them to keep growing.
  • Perennials generally have a shorter blooming period compared to annuals, so it’s common for gardeners to use a combination of both plants in their yard.
  • During the first growing season biennials produce roots, stems, and leaves; during the second they produce flowers, fruits, and seeds, and then die.
  • Sugar beets and carrots are examples of biennials.
  • While the top portion of a perennial dies back in winter, new growth appears the following spring from the same root system.
  • Perennials also tend to do best when planted in the fall or spring, no later than six weeks before the ground freezes.
  • Annuals will also typically bloom all season until frost, so you get consistent color and showy blooms.