Window boxes are an attractive way to add color to the outside of your home. They can also maximize your garden space, especially if you don't have a lot of outdoor space to being with. Choose flowers you love, but be smart in your choices. If your window box is in full sunlight, for example, choose plants that thrive in the hot sun. Consider different uses for your box as well. Most gardeners plant annuals so they can change the look of the box with the seasons.
Plant tall flowers at the back of your window box. These will fan out and nicely frame the rest of the flowers and your window. Good choices for tall flowers that do equally well in the sunlight or partial shade include geraniums and spike flowers, such as cone plants, according to the Emmitsburg News-Journal. Cosmos, which attract butterflies, and the common snapdragon are excellent annuals for any window box. Delphiniums are a good choice for large window boxes.
Most window boxes look best when filled with bunches of trailing flowers. Plant these along the edges of your window box, especially along the front edge. Vines are a popular choice, such as the ornamental sweet potato vine and ivy vines. Equally attractive are colorful trailing flowers such as vinca, which is very drought-tolerant, according to Clemson University. Lobelia is also an excellent choice, especially the bright blue variety, which can help create a wonderful patriotic display in midsummer. Moss roses are attractive window-box trailing blossoms that you can plant if you live in a warm climate.
Fill around your tall and trailing flowers with full, compact flowers that will bloom prolifically all season long. Bedding plants such as impatiens, pansies, primroses and petunias are all hardy flowers that will keep blooming if you are diligent about deadheading them (removing spent blooms). Create a springtime display by planting spring-blooming bulbs, such as daffodils and tulips, in your window box in the fall. Cover the bulbs with fall flowers such as mums, daisies and ornamental kale, which will last well into the winter in many climates.
While colorful displays of flowers are beautiful in window boxes, you may want to choose nontraditional plants for the box. Small shrubs, for example, can look very elegant in a window box. Herbs grow well in window boxes, and the boxes work to contain some that would otherwise spread too rapidly. Foliage plants, such as ferns and hostas, are attractive, especially for heavily shaded window boxes. Even succulents can make an interesting display for a window box in a desert climate.