Gardeners throw around terms like perennial, annual and biennial but do you know what these terms really mean? Annuals and perennials are the most familiar terms and are pretty easy to define. An annual plant is one that grows, blooms and dies all in one growing season. A perennial plant is one that comes back year after year but there can be a lot of confusion when it comes to defining what a biennial is. This confusion often arises because a biennial can act like an annual or a perennial. Are you confused? Well, Blooming Secrets is here to help end that confusion!
To put it simply a biennial is a plant that takes 2 years to complete its life cycle. Its first year is dedicated to growing stems, leaves and a strong root system. After a period of time where it seems to take a rest, usually during the colder temperatures that occur in the fall and winter, it completes its life cycle by bursting forth with an abundance of flowers that usually last throughout the spring and into the summer months. This sounds simple enough but this is where the confusion begins.
One trait that most biennials share is that they are prolific self-seeders. This means that after they finish blooming they generate a lot of seed which often germinates in the summer or fall and starts the process all over again. This makes the biennial appear to act like a perennial as it seems to come back year after year and if the conditions are right these seeds can germinate and grow fast enough that the plant can actually flower before the end of the year; acting like an annual flower would.
Some of the more popular flowers and herbs are actually biennials. Some examples include onions, parsley, hollyhocks, sweet william and perhaps the most popular of all pansies. Biennials are a great choice for situations where you can plant the seed or plants in the fall and winter them over in your garden for a beautiful spring display. I’ve had success doing this with pansies as well as planting wallflower seed in August and September and enjoying their blooms the following April.
Local environmental conditions can have a great deal of impact on the behavior of biennials. Many biennials require a cold period to perform their best so in garden zones 8 through 10 you may need to treat them as you would any other annual flower and their self-seeding may not be as prolific or they may not even self-seed at all. Regardless of how you define them though biennials should be part of your garden!
