Annuals, perennials, and biennials - what makes them different isn't as clear as you might think.
Put simply, annuals are plants that complete their lifecycle in a single year. They tend to be more colorful than longer-lived biennials and perennials. Let’s find out why.
Genetic survival strategies
Plants are all about reproduction, and they have different strategies to ensure the survival of their genetic information. While perennial plants invest energy into maintaining individual plants over time (and some can live for thousands of years), biennials use the first year to collect resources and the second year to produce seeds. Annuals go from seeds to seedlings to mature plant to seed production in a single growing season, and then they die. This means that they do not have the luxury of missing a chance at being pollinated. Brighter, more fragrant flowers increase those chances. Other annuals, especially those found in the desert, spend most of their life as a seed. These plants, ones that go from seed to seed in only a few weeks, are called therophytes. One big advantage to being an annual is this lifecycle interrupts many pests and diseases that might otherwise wipe out a species.
Annuals as food
Many of our food crops are annuals that must be replanted each year: corn, peas, beans, melons, squash, and most cereal grains are annuals. Some biennials are grown as annuals, for convenience sake, or because they cannot tolerate locale microclimates. These plants include celery, parsley, and carrots. Other common edibles, such as tomatoes, sweet peppers, and sweet potatoes, are actually perennial plants, but most gardeners treat them like annuals. Under the proper conditions, these plants can continue producing food year round for several years.
Seeds from annuals
As your annual plants end their growing season, you can prepare the the next year by collecting seeds. Choose seeds from the strongest, healthiest, most flavorful produce, and dry them out of direct sunlight. Some seeds may need chilling hours. Other seeds may need a short trip to the freezer (such as beans) to kill off any internal pests.
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.