When shopping at any garden centre you’ll often be faced with a choice for plants, Annuals and Perennials. There’s a lot of different varieties in each and the prices can vary too, it can be a bit overwhelming to make selection. We’re here to tell you about the differences between annuals and perennials in both the botanical meaning and the horticultural meaning.
First, let’s talk science. In botany, an annual is a plant that completes its life cycle in one year. A perennial is a plant that grows for 3 or more years. Some examples of annuals are petunias and marigolds. No matter how hard you try they will not survive long term once the life cycle is done. Examples of perennials can include hostas, daylilies, and lawn grass.
Now, let’s talk about the common way people refer to annuals and perennials. When visiting garden centres or buying plants you may see plants grouped under annuals or perennials or even see some overlap between the two. To put it bluntly, people often refer to annuals as anything that doesn’t survive our winters. Tropical plants, those sensitive to harsh winters, and anything intended for above ground planters will not survive the next year, therefore it only grew for “one” year, making it an annual.
For perennials, we refer to anything that can come back the next year following the winter if it’s hardy to our zone. Typically, a zone is a reference to the lowest temperature extremes in winter, but some charts may include other information like warmest temperatures, frost dates, and rainfall. We are a zone 2B/3 in our area. This helps determines what plants will survive when planted in the ground. For perennials to survive they must be hardy to our winter, they also need to be insulated under snow as well. If you plant a perennial in a hanging basket it won’t live to the next year and in that way, it can be considered an annual. That’s where confusion can come in.
Besides the number of years they live, some key differences you may find with annuals and perennials at garden centre’s is the way they grow. Annuals are selected for how quickly they can grow in a short time, this allows you to enjoy consistent flowers. In our climate, perennials are often chosen for how hardy they are and have different bloom times. Perennials can sometimes take years before they’re fully mature and have to be planted directly into the ground.
