What is the primary difference between annuals and perennials?

The primary distinction between annuals and perennials lies in their life cycle and growth patterns. Annuals complete their entire lifecycle within a single growing season. This means they germinate, grow, flower, seed, and then die all within one year. In contrast, perennials are characterized by their ability to live for multiple years, often returning year after year. They typically grow through the seasons, die back in winter, and re-emerge in spring, allowing them to bloom over several seasons.

This difference in lifecycle and longevity greatly influences garden design and planting strategies. For instance, annuals might be chosen for immediate color or seasonal displays, while perennials provide long-term structure and beauty to a garden.

The other choices touch upon aspects related to annuals and perennials but do not accurately capture their fundamental difference. While it's true that annuals have a shorter growing season, the essence of their lifecycle is what defines them in comparison to perennials. Saying that annuals return year after year is incorrect since that is a characteristic of perennials. The sunlight requirement can vary widely among both types depending on the specific plant species, which makes it an unreliable point of distinction.