Looking for a quick way to add curb appeal to your home? Consider a window box. Whether you fill it with lush greens or use it to add a pop of color to your home, you’ll get a lot of mileage and enjoyment out of this simple addition to your home’s exterior.
I speak from experience as my wife and I have four window boxes and reap months of enjoyment from them as they “thrill and spill” all summer long. And one of the things we love most about visiting Charleston, South Carolina, is getting inspiration from the Instagram-worthy window boxes that they are known for.
So, we went to a local expert to get some inspiration for planting window boxes in Lake Oswego. Beverly Ashenden is a landscape designer and owner of Ashenden Garden Design and helps clients with everything from designing their entire yard to individual flower beds.
First, she has some general guidelines for designing the layout of this small piece of real estate that can have such a big impact.
Start with a theme. Do you want cool colors or hot? Maybe you prefer a variety of greens that dazzle with their texture. Is there a thriller plant that you absolutely love and want to build the rest of your arrangement around? And to make your window box work year-round, consider seasonal themes like autumn with the addition of items like pumpkins or ornaments to a winter box.
Give your plants the conditions they need to succeed–that includes the proper sunlight or shade exposure. “Shade tolerant plants need to be in a shady location for good performance,” Ashenden emphasizes. Another make-or-break condition is proper drainage. Most window boxes will have drain holes in the bottom, but if not, be sure to add. For pots, Ashenden usually creates little mounds around the drain holes with pebbles or broken terra cotta pieces to prevent the dirt from plugging the holes, but that isn’t usually a problem in window boxes. And then fertilize throughout the season for good color production.
Divide your plant selection into thrillers (which go in the back), fillers (in the middle) and spillers (that will drape along the sides). When choosing thrillers, consider their ultimate height and whether or not they will be blocking any of your window view.
Use the color wheel to ensure color combinations that complement, not compete with each other. “You don’t want two colors competing with one another,” Ashenden explains. “You’re going to lose the effect of each of those colors if they do.” A simple fix is to separate them by a neutral gray or green that “settles your eye,” as Ashenden puts it.
Keep it simple. In addition to choosing a theme, Ashenden recommends picking 2-3 colors and repeating them throughout. “You can make something interesting without it being too busy,” she points out.
Consider perennials. Ashenden is a big fan of starting out with small perennials in confined spaces like window boxes and then rotating them out to bigger pots or your yard when they get too big. It’s a more economical way to go in the long run, and fortunately in the Pacific Northwest, there are lots of perennials to choose from.
Consider herbs or lettuce for one of your greens. This is an especially good choice for window boxes next to the kitchen, making it convenient when you want to go out and harvest them. In addition to adding that calm, neutral palette to your arrangement, herbs and lettuce provide interesting texture too.
Here are some flowers/plants to consider that perform well in the Pacific Northwest:
Hostas. This is a perennial filler that adds a lot of texture with an interesting leaf structure. Some varieties also produce flowers.
Bergenia. Another perennial filler, this one provides good texture and small varieties like the Ruby Elf also produce flower clusters atop their stems.
Beesia. This perennial with its heart-shaped leaves is a good substitute for ivy.
Begonia. These annuals are one of Ashenden’s favorites because of their variety, their performance in the shade and their leaf structure. In most cases these would be fillers; however, some varieties are tall enough to take the thriller spot.
Fuschia. These popular Pacific Northwest plants can thrill or spill depending on the variety you pick.
Hydrangea. My wife will look for any excuse to plant a hydrangea as she believes you can never have too many of them. They have been the thrillers in our deck window box the past two summers and performed well. The colors tended to fade over the summer, almost looking like a dried flower but they were still beautiful as far as my wife was concerned. Different varieties are sun/shade tolerant. Our deck gets morning sun which seemed to suit them just fine.
Ferns. Here’s another plant that comes in a variety of colors and textures, sure to claim the thriller spot in your arrangement. The Japanese painted fern, for example, with its blue-green fronds provides a dramatic statement as a background for the rest of the plants.
Huechera/Coral bells. This perennial is mostly grown for its leaf structure but also produces a sweet flower as well. It is a great plant to base your arrangement around. A filler, it will do well in both shade and sun
Impatiens. This annual is one of our family’s favorites both for the beautiful color choices as well as the mileage you can get out of them, blooming from late spring through early fall.
Euomymus. This is a large perennial family but Ashenden has one variety to recommend to make your search easier – the Wulong’s Ghost has a sweet variegated leaf that creates a striking spiller effect.
Lamium. This fast-growing plant is a starring spiller in many of the Costello window boxes. The variegated leaves are interesting in themselves but they also produce small flower clusters throughout the summer. It will tolerate some sun.
Creeping Wire Vine. Though considered an alternative ground cover, the creeping wire vine is also a good choice for window boxes as a spiller for its great draping qualities.
String of Pearls. While this spiller is a little on the tender side for our zone, it’s a fun one to play with because of its appearance as a bunch of peas strung together.
Caladium. If you want to add a tropical look to your arrangement, this Caladium might be a good choice for a thriller or filler, particularly the sweet variegated leaf of the Heart to Heart Chinook variety.
Boxwood. The versatile boxwood, if kept small enough, is a good foundation plant in the thriller spot of your window box that will perform well in both sun and shade.
Lemon Cyprus. These chartreuse green shrubs (or trees) luckily come in two window box sizes—smaller and smaller. At one point they may get too big for the space but they are a fun and colorful addition to start with PLUS they give you a lemony scent when you touch their leaves.
Geranium. These are the workhorses of many window boxes providing both filler and spiller functions, depending on the variety.
Lantana. Depending on the variety, these can be either a filler or spiller with the deep green leaves providing a rich backdrop to colorful verbena-like flowers.
Petunias. Along with geraniums, petunias are also hardworking choices of many window box planters. Color choices abound and they don’t require much deadheading. One word of warning—the spillers can become leggy as the summer wears on.
Bacopa. This trailing annual is one of our favorite spillers that thrives in sunny to partly sunny conditions. It comes in shades of white, pink, lavender, blue and coral red and blooms from May through October.
Marguerite Ipomoea/Sweet Potato Vine. This is another favorite spiller of ours in our sunny window boxes. The bright chartreuse foliage is a show stopper and performs all summer long.