The Basics
When you think about it, we expect a lot out of annuals in a short period of time: To germinate, grow to full-sized plants, and flower their heads off for as long as possible is a tall order. Home gardeners can help annuals fill this order by providing them with a few, very basic things:
Get the annuals in the ground whether directly in the garden or in a container as soon as spring weather has really come to stay. If you plant annuals too early in spring, they may just sit and sulk in the soil, never fully recovering or, worse yet, being killed by a late spring frost. Conversely, if you plant annuals too late in the season, you're not giving them enough time to do want they want to do, namely mature and provide a brilliant display of flowers.
Be sure to match the needs of a particular annual with the right location in your garden. Although there are notable exceptions, in the main, annuals love a full sun location. You may be able to get a sun-loving annual to put on an adequate show with only four hours of direct sun a day, but you're doomed to disappointment is you plant a sun-lover in the shade, or a shade-lover in the sun.
Although some annuals are remarkably tolerant of a wide variety of soils, you'll always get better results if you plant them in a well-drained, loose, loamy soil. If your soil is heavy (or exceptionally sandy), before planting add two or three inches of organic soil amendment (such as compost, ground bark, or peat moss) and cultivate the soil to a depth of six inches or more, incorporating the organic amendment as you turn the soil.
If you're planting annuals from seed, the back of the seed packet will provide you with specific instructions concerning planting depth and spacing. If you're planting annuals from already-started transplants, remove each plant gently from its growing container, keeping its rootball intact. Plant the transplants at the same depth as they were in their nursery containers, pressing the soil gently around them with the palms of your hands. If possible, plant transplants on a cloudy day, or in the early evening, to keep wilting to a minimum. And always give newly planted annuals a good drink of water to settle the soil and refresh their spirits.
Some of the newer varieties of annuals are "self-branching" and don't require that you pinch the growing tip out of the young plant. While you're at the nursery or garden center, be sure to ask whether or not the plants you've selected require pinching. It's amazing what this one small step can do. With it, your plants will likely mature into well-branched, bushy specimens that don't require staking. Without pinching, tall plants may simply fall over and struggle to mature, never really amounting to much.
Although a few annuals are remarkably drought-tolerant, you'll get the most from them if you provide water on a consistent basis. The soil can be allowed to dry out slightly between waterings, but it should never be overly wet. And to keep diseases to a minimum, water the soil without wetting the foliage.
Because so much is expected of annuals over a short period of time, good gardeners provide them with monthly applications of a complete fertilizer (such as a 10-10-10 formulation). Whether it's liquid or dry makes little difference. Just make sure these willing performers receive the nutrients they need, right through late summer or early fall.
To keep annuals blooming at the peak of their ability, deadhead regularly. By "deadheading," we mean removing (either with shears or by pinching) all spent flowers. Once a flower head has reached the point where its seeds are mature, the plant will usually stop producing flowers. If you want plenty of flowers, be vigilant about removing the dead and dying blossoms from the plant.
If you're out in your garden of annuals on a daily basis, it's easy to keep a sharp eye out for any potential damagers, like pests and diseases. Bear in mind that the most valuable phrase regarding healthy plants is "at the first sign of attack." If you apply a control in the earliest stages of infection, the amount and strength of any insecticide or fungicide needed will be minimal. Once a pest or disease has really taken hold, stronger methods and controls will be needed. So get out there in your garden every day, inspecting and enjoying your plants, and don't let any pest rob you of a single flower!
Although there are some annuals that produce foliage only, for most gardeners the word "annual" is synonymous with colorful garden flowers that bloom from early spring right up through the first fall frost. For the record, an annual is defined as a plant whose life cycle is complete in a year's time, sometimes slightly less. Most annuals are planted in the garden from seed or transplants in spring, flower throughout the warm months, and are then killed with the first frost in autumn.
To put it indelicately, home gardeners get "a lot of bang for their buck" with annuals. Sure, they are temporary, but what a temporary show they put on! Of all the types of plants available (trees, shrubs, vines, perennials, bulbs), annuals are usually the least expensive of the lot. And if you decide to grow them from seed (as opposed to already started plants), they're positively cheap.
The diversity within the group of plants known as annuals is staggering, with everything from 10-foot-tall sunflowers to the ground-hugging sweet alyssum to the rampant, vining morning glory. From landscape displays to containers and hanging baskets, there is truly an annual for every occasion and situation. And when it comes to cut flowers, it's hard to beat annuals for their sheer production and ease of growing.