The Best Types of Flowers for Your Window Boxes

One low-maintenance way to add a pop of color to the exterior of your home is by installing a window box filled with your choice of flowers and greenery. According to Adam Dooling, curator of outdoor gardens and herbaceous collections at the New York Botanical Garden, there are many reasons why one may choose to use window boxes to satisfy their green thumb. "For people that live in apartments or cities, it may be their only way to grow plants," he says. Dooling also notes that the "frequent change-outs that window boxes often require allow the gardener to try lots of different plants over the course of the growing season."

If you're interested in adding a window box to your property, there are a few things to consider before choosing the varieties you're going to grow. Dooling says to think about the mature size of the flower and the depth of its roots, which will dictate the size box you buy. Additionally, he says to determine whether or not you want to grow one type of flower in your boxes—or create a mix. "If so, how do the plants perform in relation to each other?" he shares. Once you've answered these questions, think about your growing conditions. Which direction is your window box facing? How much sun or shade does it receive? These answers will help you decide which types of flowers to plant. You'll also want to create healthy growing conditions for your varieties by using a quality potting mix and making sure your window box has drainage holes, so excess water can seep out when the reservoir is full.

Now that you have a basic understanding of window box logistics, let's move on to the best part—which involves the flowers you plant inside them. Ahead, two experts outline which blooms perform best in these fixtures.

Full to Partial Sun Flowers

Once you have an understanding of your growing conditions, you'll know whether you should purchase flowers that prefer full sun, partial sun, or full shade. Sunny sites offer more options for colorful flowering plants, like calibrachoas, a perennial that's commonly seen in shades of violet, blue, pink, red, magenta, yellow, bronze, and white. According to gardening expert Melinda Myers, most petunias also do well in full to partial sun. "Look for those that also claim heat and humidity tolerance," she notes. If you're hoping to attract pollinators to your sunny spot, Meyers says heliotrope has fragrant flowers that hummingbirds and butterflies love. Additionally, pentas—another butterfly favorite—blooms all season long and prefers full to partial sun. Another choice Meyers recommends is summer snapdragon, which (as its name implies) is perfect for the warm-weather season and features upright plants that are available in several colorways.

Shade or Partial Shade Flowers

Typically, shade-loving plants and those that tolerate moist soil go hand in hand. If you have a nearby tree or structures that covers your window boxes or reduces their sun exposure, consider shade-tolerant flowers. Meyers suggests fuchsia, which needs shade and moist earth; avoid windy locations, she explains, if you choose this option. Additionally, tropical plants that are often grown as houseplants, like philodendron, inch plant, and ivies, perform well in shaded window boxes, according to Meyers. Additionally, begonias, including the tuberous and rex types, are shade tolerant and add a nice textural element to your space. Other flowers that perform well in shaded window boxes are browallia, torenia, impatiens, dwarf hostas, and hellebore.

Drought-Tolerant Flowers

According to Meyers, drought-tolerant plants prefer dry soil once they're established, which she says "makes them good choices for containers and window boxes, especially for busy gardeners or those who tend to under-water their plants." She notes that these types of flowers still need regular attention but are able to tolerate drier soil and thus can handle less frequent watering. Drought-tolerant plants include mandevilla splendens (often listed as dipladenia), as well as zinnias, which come in a variety of sizes and colors. "Look for those like profusion and zahara that have good disease resistance," Meyers suggests. Additionally, Meyers lists icicles licorice, also known as helichrysum, as a great heat- and drought-tolerant plant.

Trailing Plants

If you want to create a cascading effect with the plants in your window box, consider opting for a few trailing flowers. There's a handful of options to choose from, such as silver falls dichondra, which Meyers describes as a silver foliage that drapes flat against the box. There's also lotus vine, which features fine lacy leaves, as well as petunias, calibrachoas, verbenas, mandevillas, bidens nasturtiums, trailing lobelia, viola, alyssum, and "many beautiful types of plectranthus," Dooling notes. He also says many varieties of ivy, as well as some sedres and grasses, can also create a cascading effect.