Annual plants are a great way to add quick color to your landscape. These easy care plants can be changed out with the seasons. This article gives tips on care, planting and design.
Annual plants grow, set seed and die in less than a year in most climates. There are two seasons of annual plants, warm and cool, however there are a few annual plants that thrive during both seasons.
Warm Season Annuals
Warm season annuals like petunias, lobelias, marigolds and cosmos are planted in early spring and live until a winter frost kills them. Warm season annuals can be planted indoors from seed 6 weeks before spring.
Cool Season Annuals
Cool season annuals like pansies, snapdragons and stock are planted in late summer or early fall and bloom until hot summer temperatures kill them. Start cool season annuals from seed in late summer in a partial sun location.
Plants That Can Be Both Warm and Cool Season Annuals
In mild climates, some annual plants can live during both seasons. Nasturtiums and calendulas are examples of annual plants that grow well in both spring and fall. However, neither nasturtiums nor calendula(s) can live through a very hot summer or survive a winter frost and must be replanted at the beginning of each season.
You can find annual plants locally at nurseries and garden centers, or you can plant them from seed. If you decide to plant seeds, you’ll want to read Gardening 101: Planting Seeds. If you plant your flowers from transplants, read Gardening 101: Planting Transplants.
Stores that don’t specialize in caring for plants may unknowingly sell annual plants near the end of their planting season. For example if you bought snapdragons in early summer instead of fall, you would only have them for a week or so until the hot weather killed them. Make sure you either know which kinds of annual plants grow during each season, or that you purchase them from a reputable nursery or garden center.
To keep annual plants blooming, you’ll need to remove old flower heads, a process known as “dead-heading.” This encourages plants to flower instead of make seeds. To prevent plants from getting too leggy and overgrown, pinch back stems to encourage more compact growth.
Some annuals may grow tall and have a tendency to flop over. You may need to stake them with bamboo. Or to avoid the need for staking, plant them near a fence and fasten them to it with twine.
As the season comes to a close, stop deadheading annuals and let flowers set seed. Some seeds like snapdragons, pansies, and impatiens are tiny and may scatter before you can catch them. Other seeds like calendula, sweet pea and sunflower are large and easy to save.
For small seeds, wait until the flowers change into seed pods and then tie a small paper bag over each pod. Check the seed pod to see when it is dry, and then gently twist the pod off into the bag. Next, crumble the seed pods between your hands to remove the seeds. If needed, use a sieve to remove the “chaff” or save it along with the seeds and plant it. Put the seeds in a small paper envelope with the name and the date. Annual flower seeds usually last for about 1-2 years.
Some annuals are considered “self-sowing” and will spread themselves in the garden without help. Warm season self-sowers include cosmos, four-o-clock, impatiens, love-in-a-mist, bachelor buttons, and calendula. Cool season self-sowers include sweet pea, snap dragons, poppies, and calendula. Self-sowers may not always pop up where you want them, but you can always move them when they are small. Some annuals are weedy and may self-sow all over your garden.
Flower Fun-Warm Season
For an edible warm season annual plant, plant scarlet or lavender runner beans. You’ll need a fence or trellis to support them. Runner bean blossoms attract insect pollinators and hummingbirds. Once the bean pods dry, collect and save the seeds in a cool, dry place until the following year. Read A Bean Worth Drying by Linda Ziedrich to find out more about them.
Flower Fun-Cool Season
For a fun winter project, plant climbing sweet peas on an old patio umbrella. Just remember, this project requires some cleanup work after the sweet peas are done. Read more about planting sweet peas in Sweet Peas=Spring!
photos by Holly Guenther