We will take a quick look at annual vs biennial vs perennial:
An annual is a plant that will complete its entire life cycle in one year. There are two groups of annual plants, summer annuals and winter annuals. Summer annuals will germinate in the spring, flower, seed and die by the winter. Winter annuals germinate in the fall, over-winter, flower in the spring, seed and die by summer. Both of these groups are annuals and complete their life cycle in one year. Some examples of annuals are marigolds, tomato plants, ragweed, etc.
A biennial is a plant that will complete its entire life cycle in two years. This category is a smaller category of plants. A typical biennial plant will grow a rosette in the first year of it life. Typically the top will die back for the winter, then in the second year it will flower and seed, then die at the end of the second year. Some examples of biennial plants are wild parsnip, common evening primrose, Queen Anne’s Lace, etc.
A perennial is a plant that will complete its entire life cycle in at least three years if not more. Many times it is thought that a perennial plant will live on indefinitely. This is not the case. All plants do have a finite life span. Now there are some that can live for hundreds and even thousands of years like the Giant Sequoias in California. On the other end, a strawberry plant may be able to live up to six years under ideal conditions. Both of these are perennial plants. A perennial will typically flower multiple times in its life. For the vast majority of perennial plants, under healthy conditions, it will flower every year.
The location and climate of the plant can change what category the plant fits into. Certain plants are annuals in one location, and they may be perennials in other locations. The climate can play a key role in deciding what category the plant falls under.