Once you've decided where to put color and what color works best in your landscape, you must decide how to arrange the plants.

When arranged properly, color flows through a garden like a well-orchestrated piece of music. In reality, there are numerous pitfalls to placement that can ruin a harmonious planting. Here are things to avoid, and ways to go with the flow.

Avoid alternating colors, one by one. A mass of one color creates more impact and is less confusing to the eye than a mishmash of different plants. A collection of one color is referred to as a sweep. Garden designer Fred Thode of Clemson, South Carolina, likes tadpole-shaped beds of each flower type. Thicker at one end than the other, these sweeps naturally provide a sense of movement in the border. It's easy to achieve this shape. "Simply use a garden hose to lay out your color," Fred suggests. Make a big loop, and then pull it so that it's longer than it is wide. Where the ends cross will be narrower than the curved side of the loop. If you plant several tadpole-shaped sweeps of color together, the garden will have an organized, tapestry-like appearance.

Don't arrange bedding plants like soldiers, arms length apart. When planting annuals, space them evenly, usually about 3 to 4 inches apart. This way, they will fill out and cover the bare bed in the first month or so. This ideal spacing prevents competition between plants and will shade the soil to keep out weeds. The flowers grow together to present a seamless, unified appearance.

Avoid planting annuals in neat and tidy rows all in perfect alignment. Plant in a staggered grid. Set out the first row, and then position your second row behind the first, but aligned between the ones in front. The third row will be directly behind the first row and so forth. Use the length of your trowel, or a portion of it, as a gauge to keep the spacing constant.

Don't make things too perfect. The difference between a home garden and a commercial one is the element of surprise. Garden designer Ruthie Lacey in Columbia, South Carolina, says, "I mass plants and use curves. But then I like to put one plant out of place, so it looks natural." Add a visual blip to the garden to keep it from becoming static. A pot placed in a bed gives an unexpected thrust of height. Flowers spilling into a walkway soften a hard edge.