Which is the better choice, annual plants or perennial plants? That depends on your preference. Perennial plants are economical because they return every year, but they usually flower for a shorter period of time. Annual plants usually flower throughout the growing season. Both can be very colorful, but annual plants produce flowers for a longer time within a growing season. Perennial plants tolerate dry conditions better, while annual plants require water and fertilizer to keep them blooming. Annuals can be replanted or changed each year, while perennials are more of a commitment to blooms the following year.
An annual plant completes its entire life cycle from seed to flower to seed within one growing season. The entire plant will die at the end of the growing season. The seeds are the connection between each generation. Sometimes the seeds of an annual plant will survive our winter and germinate the following spring. The photo shows bachelor buttons, which have reseeded themselves in our butterfly garden.
A perennial plant lives for many growing seasons. Often the stems and leaves will die back but the roots remain alive under the soil throughout the winter and will send up new shoots the following spring.
Another type of plant is a biennial, one that has a life span of two growing seasons. During the first year, the plant will usually produce a small rosette of leaves, and the following year it will have a colorful show of flowers that produce seeds. Examples of biennials are foxglove, delphinium, primrose, and poppies. Since their seeds sprout the following spring, it becomes easy to have plants from either the first- or second-year cycle mixed in a flower bed, which makes it appear that these plants are perennials.
Another variable to consider is our climate. Here in western New York, our plant hardiness zone or climate range dictates how well plants survive through the winter. Plants we consider annuals can be perennials elsewhere. Petunias, rosemary, and lantana are perennials in some southern states.
So, how to plan your garden? If you use perennial plants, it is wise to know when they usually bloom. Planting perennials with different bloom times will provide a wave of flowers as the season progresses. Examples are crocus and daffodils in the spring, which grow from bulbs. Peonies, daylilies, cone flower, black eyed Susan, and chrysanthemums are examples of perennials that bloom at different times.
Annual plants include vegetables, marigolds, petunias, and zinnias. Annual plants that drop seeds which survive our winters include cleome, cosmos, forget-me-nots, and bachelor button. Oftentimes nothing needs to be done with these seeds, as the seeds survive on the soil’s surface and will germinate once the sun warms the soil in the spring.
Informative links from New York Cooperative Extension websites: