The Best Flower Annuals for a Window Box

Create a window box with annual flowers.

Window boxes filled with a variety of colorful, flowering annuals are an eye-catching way to express your unique gardening personality. A dynamic flowering window box enhances your home's landscape and also attracts butterflies and hummingbirds. To select the best annual flowers for a window box, first consider the location and the micro-climate of your window box. A sunny window box location is best for flowers that tolerate full to partial sun. Shady to partially shady locations are best for shade-tolerant flowers. Soil depth and plant height are also important considerations. Select annual flowers that grow no more than 12 to 15 inches tall, and don't require more than 8 to 10 inches of soil.

Geraniums

Geraniums are excellent window box flowers.

Geraniums are an excellent annual flower to plant in a window box. If you have window boxes situated where there is full to partial sun and also full to partial shade, geraniums will thrive in both locations. Geraniums come in a variety of growth habits, from trailing to upright, and in many different leaf patterns and colors. Trailing varieties are ideal for window boxes as their flowering branches grow downward and make a showy display. Upright geranium varieties are attractive companion flowers to plant in window boxes. Their blossoms can be double or single in colors of pink, white, coral, red, fuchsia, lavender or multicolors. Geraniums have a variety of scents such as lemon, peppermint, rose and nutmeg. They bloom from early summer through late fall in eye-catching splashes of color. Geraniums need very little care after they are planted. Simply deadhead spent blossoms to promote continuous growth and water lightly as needed.

Calibrachoa Million Bells

Calibrachoa Million Bells bloom profusely all summer.

Calibrachoa million bells is a fast-growing flowering annual that excels when planted in a window box situated in full sun. Its cascading branches grow downward in window boxes and are literally covered with petite, bell-shaped flowers from early summer through late fall. Calibrachoa has a compact growth habit and spreads to about 2 feet. One or two plants of different colors can easily fill a window box when full-grown. The million bells variety offers blossoms in colors of soft apricot, hot pink, cherry pink, white, lavender-pink, purple-blue and yellow. A slow-release or liquid fertilizer is recommended to promote healthy growth and continuous blooming.

Verbena

Verbena flowers are spectacular in window boxes.

Verbenas are an impressive half-hardy annual flower to plant in window boxes. Both trailing and upright varieties thrive in window boxes situated in full to partly sunny locations. Verbenas bloom with round clusters of small, fragrant flowers at the ends of their branches. Because they bloom continuously from early spring through late fall, they will attract many butterflies. Verbenas come in a variety of blossom colors including peach, salmon, white, red and purple, and are also available in multicolors. Some popular trailing varieties are: Azetc, Babylon, Carousel, Pink Parfit, Imagination and Silver Anne. Deadhead spent blossoms to promote continuous blooming and neat appearance.

Wave Petunias

Wave Petunias in window boxes are stunning.

Wave petunias are stunning annuals that thrive in window boxes. They are very heat tolerant, they don't need to be pinched back and they require only minimal maintenance after planting them in window boxes. These amazing petunias grow less than 12 inches tall, depending on variety, so they won't obscure your window. Because they form hundreds of tiny blossoms on the long branches that grow downward, they make a dynamic impact in window boxes. Wave petunias come in five different series: Wave™, Easy Wave™, Double Wave™, Shock Wave™ and Tidal Wave™. They bloom in shades of white, blue, lavender, rose, red, pink, lilac and lavender from early spring until late summer. Wave petunias are also more resistant to disease than other petunias.

References

• North Carolina State University Extension: Geranium Culture for Home Gardeners; Alice B. Russell; December 1997
• University of Illinois Extension: Hort Answers: Annual: Garden Verbena
• University of Minnesota Extension: Outdoor-Indoor Geranium Culture; Debora Brown and Harold Wilkins; 2009
• Landscape America: Making your garden grow better and healthier: Wave Petunias
• Mississippi State University: Southern Gardening: Calibrachoa give prolific flowers all season long; Gary R. Bachman; May 2010

Resources

• About for Dummies: Home and Garden: Gardening: Planting a Window Box Container Garden