Annual Flowers: What to Know to Help Them Thrive
Follow these tips to achieve a bountiful, colorful garden full of annual flowers.
Look for the best deal
Young plants in six- or eight-packs of the same variety are often available at very low prices. The seedlings should be well rooted but need not be in bloom. Once planting season is past, however, beware of starved, dried-up leftovers. Here are other secrets your gardening center won’t tell you.
Looking to hide something?
Climbing annuals will quickly disguise a chain-link fence or the screening around garbage cans. Morning glory, scarlet runner beans, black-eyed Susan vine, sweet peas, and hyacinth bean are some of the climbers that do the job nicely.
These are best for shady gardens
Impatiens, monkey flower, nasturtium, California bluebell, and wishbone flower are shade-tolerant annuals. Or check out these other flowers that grow well in the shade.
Choose these for pots and window boxes
For pots and window boxes, choose bushy or trailing annuals. Petunias, marigolds, verbenas, thunbergia, lobelia, and heliotrope are ideal. But avoid tall plants like sunflowers, which look awkward in small containers.
Make sure to plant in the right place
A sunny location with good drainage is more important to most annuals than soil quality.
Use them as fillers
Plant annuals in the empty spaces between shrubs, foundation plants, perennials, or rows of vegetables.
Sow half-hardy annuals indoors to give them a head start
To make sure they’re evenly spaced, place chicken wire over your seeding tray and put a seed in each hole. This makes it easier to separate the seedlings for transplanting. You can also start growing these vegetable plants indoors before spring.
Fill your garden with flowers all season
While you wait for perennials to take hold, dress up the garden with annuals. Since they germinate, bloom, and die within a single season, there’s no need to dig them up once the later flowers are established.
Consider your color combinations
Massing a single color will create an elegant, unified effect suitable for terraces, planters, and window boxes. Pastels—white, pinks, lavenders, yellows—show up best in early morning and evening light. If you want a multicolored effect, make a sketch and color it in; it will help you keep the colors harmonious.
Keep them good and wet
Plenty of moisture is essential when you set out young plants. First, soak them in a tub of water. Plant only after the root ball is thoroughly wet. As extra insurance, soak the planting hole with a good watering as well.
Annuals don’t like manure—even when it’s well aged.
Too much nitrogen results in plants with too many leaves, too many stems, and too few flowers. The only manure suitable for use on annuals is one that has dried for at least two years.
Should you pinch your plants?
Pinching young plants delays blooming but helps them become stockier and bushier. Annuals such as clarkia, sweet pea, cosmos, godetia, coleus, snapdragon, nicotiana, red salvia, and petunia benefit from pinching. Use your thumb and forefinger to nip out the growing tip of the main stem just above a leaf or pair of leaves.
Which to deadhead
Use shears or scissors to remove dead flowers from annuals that bloom in flushes, like coreopsis, petunias, California poppies, and marigolds.
Put annuals into pots at the end of summer
Species such as coleus, impatiens, browallia, geranium, floss flower, and wishbone flower will provide attractive blooms in your home for several months.
Want more gardening tips?
This A-Z guide covers everything from acid soil to zucchini, with hints and tips culled from leading horticulturists and accomplished home gardeners from all over the country. Learn more about the Reader’s Digest Quintessential Guide to Gardening and buy the book here.