What Is An Annual, Perennial, And Biennial Plant?
Don’t know what is the difference between annual, perennial, and biennial plants? Read this article to find out.
If you’re passionate about gardening, flowers, or plants in general, you’ve probably come across terms such as “annual, perennial, or biennial plant.”
Every plant falls in one of these three categories (flowers, fruits, vegetables, trees, grass, etc.). In order to provide the proper care for a particular plant type, it is important to know first what these terms mean and determine in which one of these categories it goes.
Annual, biennial, and perennial are three categories that refer to a plant’s life cycle. Below, I’m going to explain the particularities of every classification.
What is an annual plant?
Annuals are those plants whose life cycle begins in spring, starting with the germination of the seeds and ending during the same year with the production of new seeds. This cycle can either start in spring and end in autumn, or the seeds can germinate during fall and reach the maturity and die in the subsequent spring or summer.
After an annual plant ends a life cycle, all its parts die, including roots, leaves, stalks, flowers, and so on. The full responsibility for the reproduction of the plant is passed to the seeds produced by the plant before the end of the season.
In favorable climatic conditions, an annual plant can produce large amounts of seeds and can multiply so abundant that it can give the impression that it is perennial.
There are many plants that fall into this category. Below are a few examples of common annual plants that many of us grow in the garden, or around our house.
Example of annual plants
- Most radish varieties
- Common sunflower
- Sweet corn
- Winter melons
What is a perennial plant?
Perennials are those plants that have a lifespan of more than two years.
The duration of the life cycle of these categories of plants is not limited to a certain period. In favorable climatic conditions, a perennial plant can live for many years. Of course, this will vary from one plant to another.
Unlike the annuals that die completely each season after the production of seeds, the perennial plants continue to grow and produce fruits, flowers, and seeds year after year.
Even though the foliage and the aerial part of most perennial plants perish during the cold seasons, the root system of perennial plants remains active in the soil.
When the new season arrives and the proper climate conditions are met again, the plant will regrow from the same roots and repeat the cycle.
However, not all the plants that fall into this category lose their foliage during winter. Numerous perennials keep their leaves all year long and because of this ability, some of these plants are often times used as decorative plants in landscaping activities.
Perennial plants can be classified further into herbaceous perennials and woody perennials.
Many perennials have developed different adaptations to get through the winter or dry periods. Unlike annuals who mainly reproduce through seeds, most perennial plants multiply by vegetative reproduction such as rhizomes, bulbs, roots, tubers, and less often by seeds.
Diverse types of herb, vegetables, and flowers we cultivate in our gardens are perennials. Still, because of the variety of climate conditions globally, many of us grow them as annuals.
Probably one of the best examples here is the one of tomato plants. Even though almost everybody grows them as annuals, tomatoes are perennial plants.
Example of perennial plants
What is a biennial plant?
Biennials are those plants who need two years to complete their life cycle.
In the first year, these plants develop roots, stems, and leaves. During the winter season, most biennials go latent. The following year, their stalks elongate, produce seeds to secure the plant reproduction, and then die.
Therefore, note that unlike perennials and annuals who complete a full life cycle in a single year, biennials require two years to reach their maturity. The plants then die and don’t come back the next season.
Winter’s cold and frost stimulates biennials flowering and seed production processes. To artificially speed up the whole cycle, some gardeners, keep the seeds in the freezer and then in the refrigerator before planting.
This approach can reduce the cycle of some biennials from two years to several months, hence, making biennials behave like annuals.
Some biennials are intentionally grown as annuals because they offer all the edible parts in their first year of life (eg. carrots, celery, parsley, cabbage). In the second year of life, many biennial plants lose some of their benefits and flavor because they use the nutrients to focus on seed generation, a process necessary to ensure plant reproduction.
Example of biennial plants
- Brussels sprout
Hardy, Half-hardy, and Tender
Frequently, when it comes to classifying a plant into one of these categories based on its life span, you may also encounter terms like hardy, half-hardy, and tender.
These terms, followed by annual, perennial, or biennial are utilized to refer to a plant’s tolerance to frost and cold.
Hardy plants can tolerate cold weather better than half-hardy plants and much better than tender types, which require higher temperatures to germinate and grow.
- Hardy – typically used to describe a plant that can survive a freeze or frost.
- Half-hardy – referring to plants that can survive only a short period of light frost.
- Tender – used to describe plants that cannot withstand cold weather or frost of any kind.
Examples of garden vegetables and herbs:
- Hardy: spinach, cabbage, broccoli, onion, Brussels sprouts, kale.
- Half-hardy: carrots, lettuce, radishes, celery, cauliflower, Swiss chard.
- Tender: tomatoes, cucumbers, beans, eggplants, peppers, squash.
Annuals, biennials, and perennials are the main classifications of plants based on their life cycle. All plants fit into one of these three groups.
It’s important to know in which of these categories each plant falls into to understand the way that particular plant propagates, when to expect it to produce seeds, when to harvest, whether to extract it up in the fall or leave it to and wait for it to come back in the spring, ad so on.
Now you know which are the differences between annual, perennial, and biennial plants.