Choose brightly colored annuals. Violas are almost always a good option since they will thrive in almost any U.S. climate. One of the ways professional garden designers boost the intensity of their plantings is by grouping colors together in large masses. Remember that colors lose impact if they're spread far apart.
Properly prepare the soil by spading the entire plot. We recommend a spading fork rather than a shovel. Add 3" to 4" of compost to the plot. Mix in the compost with the soil and rake smooth.
Position your plants before planting to determine the desired layout. Always plant from back to front to avoid having to walk over plantings. Space plants tightly, nearly root ball to root ball. This is usually an unorthodox approach, but annuals don't live long enough for their growth to be a concern. Tight spacing also allows for one plant to die without leaving a noticeable gap. Offset the rows of plants to avoid any appearance of a grid design. The design should be natural and flowing.
Be sure to water the entire bed after planting. If you notice any wilting before you've finished planting, stop and water that section. If you are watering during the day, take care to avoid getting water on the foliage. Water on foliage with the sun shining can act like a magnifying glass and damage plants.
The key to long-lasting beauty in annuals is the prevention of seed production. When a plant starts producing seeds, it slows its metabolism, quits blooming and even dies. For example, after an annual like this marigold has bloomed (Image 1), the bloom fades (Image 2) and then dries out (Image 3). If the flower reaches this final stage, the plant will react as if the season is over and it will begin seed production. To prevent this natural process from occurring and to keep the plant blooming, check your plants every day and clip off any faded blooms. This simple step will pay enormous dividends in maintaining the color of your plantings for as long as possible.
The key to keeping annuals healthy and in bloom is consistent nutrition. Fertilize with half of the manufacturer's recommended dosage, but doing so twice as often. Fertilizing generously and regularly gives annuals a stable diet, encourages more consistent blooms and will keep this finished project looking beautiful. Make sure to thoroughly mix the water and fertilizer so that the fertilizer doesn't simply settle at the bottom of your watering can.
Water the bed after fertilizing so that the nutrients are sent deep into the root zone. This technique will make any fertilizer you use more effective. You should fertilize your annuals every two weeks.