An annual is a plant that completes its life cycle, from seed to bloom and back to seed again, all in a single growing season. A practical definition of annuals could be plants that must be replaced every year in the garden. They are the work horse of the flower garden, blooming from Spring through Fall.
Simple to plant and easy to maintain, annuals can turn your yard into a beautiful garden almost instantly, providing color and visual appeal all summer long. For masses of constant color in beds or containers, annuals are the best choice. Annuals are commonly grouped as hardy, half-hardy or tender.
Hardy annuals such as pansies and ornamental kale are grown for color in cool and cold seasons. They are usually planted in the fall. Most decline or die with the onset of summer heat.
Half-hardy annuals such as allysum and dianthus can tolerate light frost and are usually planted in early spring for spring and early summer color. They usually decline in summer heat but may bloom again in the fall.
Tender annuals such as vinca, zinnia and impatiens cannot tolerate freezing temperatures. They should be planted in the spring after all danger of frost is past.
Annuals allow you to experiment with different designs and colors every spring. Since there are an infinite number of varieties available, you can plant different ones year after year and never run out of shape or color choices, to keep your garden looking beautiful.
Most annuals need full sun for at least 4 to 6 hours a day to flower well. Choose shade-tolerant species such as impatiens, coleus or begonias for locations that receive less sun. Avoid planting in areas where water stands after a heavy rain. Also avoid areas near large trees and shrubs that may have many thirsty feeder roots.
As the flowers fade, remove them (dead-head) before seeds are formed to keep plants looking attractive and encourage continuing flowering. Heavy pruning can invigorate some species. For instance, petunias can be cut back in midsummer to within a few inches of the ground, fertilized and heavily watered, and they will be full and attractive again in just a few weeks.
Most annuals are grown from seed and perform best if given a head start, especially in northern climates where the growing season is shorter. They can be direct-seeded in prepared beds, started indoors for transplanting outside later or purchased as ready-to-plant transplants in pots or flats from local greenhouses, garden centers or retail growers.
Many annuals give off a scent, so you can add some wonderful fragrances to your garden, as well as their visual pleasure. Try dianthus, sweet alyssum, candytuft, petunia, heliotrope, or sweet pea. To get the most enjoyment from these and other fragrant plants, position them where your nose will find them: on a deck in containers; close to a window; and on the edges of your garden, patio, pathway or porch.
Once transplanting is complete, water the plants thoroughly. Pay especially close attention to watering the first few weeks while plants develop their root systems. Adequate moisture is essential for the growth of flowering annuals. Most annuals need at least 1 to 1½ inches of water per week from rain or irrigation. More may be needed during very hot weather.
To promote deep root growth, water thoroughly and deeply. Allow the soil surface to dry before watering again. Soaker hoses and drip irrigation are ideal watering methods since they save water and avoid wetting leaves and flowers.
Choose insect-and disease-resistant species and cultivars when possible. Keep the garden clean and weed-free, and be alert for early signs of trouble to reduce the need for pesticides. To prevent the spread of leaf diseases, avoid overhead watering if possible and water early in the morning to allow the plants to dry quickly. Overwatering can lead to root decay.
Mulch flower beds with 2 to 3 inches of pine bark or pine straw to help conserve soil moisture and reduce weed growth. Mulches shade weed seeds and prevent their germination, eliminating or reducing the need for hand or chemical weed control.
Uses for Annuals:
seasonal deck and patio containers or planters
adding a splash of color to dark areas of the garden
create a border to edge your walkway or house
window boxes, planters and hanging baskets
cutting gardens - for fresh cut flowers all summer long
fill in spaces when your perennial garden is in between blooms
create a formal garden to tame a wild space
plant a relaxing informal garden with a free flowing design