The Best Types of Flowers for Your Window Boxes

Growing flowers in window boxes is a low-maintenance way to add a pop of color to the exterior of your home. Window box gardens are also ideal for apartment dwellers with limited space, says Adam Dooling, curator of outdoor gardens and herbaceous collections at the New York Botanical Garden. Before trying window box gardening, Dooling says you’ll need to consider which varieties you want to grow, the mature size of the flowers, and the depth of the roots, so you can determine the size box you need to buy.

We spoke with gardening experts for everything you need to know to grow beautiful window box flowers that last all season.

Flowers That Grow in Full to Partial Sun

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. Here are some options:

• Calibrachoa: Sunny sites offer more choices for colorful flowering plants, like calibrachoa, a perennial that's commonly seen in shades of violet, blue, pink, red, magenta, yellow, bronze, and white.
• Petunias: 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.
• Heliotrope: If you're hoping to attract pollinators to your sunny spot, Meyers says heliotrope has fragrant flowers that hummingbirds and butterflies love.
• Pentas: Additionally, pentas—another butterfly favorite—blooms all season long and prefers full to partial sun.
• Snapdragon: 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.

Flowers That Grow in Shade or Partial Shade

Typically, shade-loving plants and those that tolerate moist soil go hand in hand. If you have a nearby tree or structures that cover your window boxes or reduce their sun exposure, consider shade-tolerant flowers. Here are plenty of suggestions from Meyers.

• Fuchsia (avoid windy locations, says Meyers)
• Philodendron
• Inch plant
• Ivy
• Begonias (tuberous and rex types)
• Browallia (bush violet)
• Torenia (wishbone flower)
• Impatiens
• Dwarf hostas
• Hellebore

Drought-Tolerant Flowers for Window Boxes

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 can tolerate drier soil and thus can handle less frequent watering. Drought-tolerant plants include the following:

• Mandevilla splendens: This plant is often listed as a Dipladenia plant.
• Zinnias: "Look for those like [hybrids] Profusion and Zahara that have good disease resistance," says Meyers.
• Icicles licorice: Also called helichrysum, it is heat- and drought-tolerant, says Meyers.

Trailing Plants

If you want to create a cascading effect with the plants in your window box, consider opting for a few trailing flowers. Meyers particularly likes silver falls dichondra, which she describes as silver foliage that drapes flat against the box, and lotus vine, which features fine, lacy leaves.

There are other trailing plant options to choose from, including the following from Meyers and Dooling:

• Petunias
• Calibrachoa (also called million bells)
• Verbena
• Mandevilla
• Bidens (also known as Spanish needles)
• Nasturtium
• Trailing lobelia
• Viola
• Alyssum
• Plectranthus
• Ivy
• Sedges and grasses