A winter annual is a plant that germinates in fall, overwinters, blooms in spring, and then dies off after it sets seeds. Such plants can add color to a garden in addition to protecting the soil and preventing erosion. In nature, they are an important part of the local ecology. For gardeners, some winter annuals are considered weeds, and they can sometimes cause problems for existing plants by trapping pests, while others are ornamentals that may be deliberately planted.
These plants are also known as hardy annuals. Like other plants considered annuals, they live for a single year only and will often reseed themselves. They tend to be low to the ground, reflecting the need for protection from harsh weather. In the snow, the winter annual will thrive buried under the snow and will be among the first plant to return in the spring. In regions where it does not snow, winter annuals may be coaxed into flowering very early.
Gardeners can seed winter annuals or plant seedlings. They should receive some fertilizer to support them through the winter, along with mulch to limit frost damage. Once established, they can largely be left alone until they start to flower. Pinching back blooms will promote a longer flowering period, and gardeners can also trim away foliage as it starts to die back to keep the plants looking tidy. Once the winter annual goes to seed, gardeners can choose to save the seeds for replanting, or let them propagate themselves.
Many of these cold-hardy plants will grow well in containers as well as directly in the ground. Flowering kale is a popular winter annual in many regions of the world thanks to its hardiness and colorful foliage, which add texture to a garden in the grim winter months. Some other winter annuals include pansies, calendula, violas, dianthus, larkspur, and sweet peas. In temperate climates, the growing season for these plants can be prolonged, and they may bloom well into the summer months.
Winter annuals are often available from nurseries at varying prices. Gardeners can also receive them through gardening exchanges. These can be a good resource for obtaining rare or unusual plants, including hybrids that may not be sold on the open market. It is also possible to ask for seeds if a gardener has an interest in a particular winter annual; gardeners are often happy to share seeds and provide cultivation tips.