What are the best flowers for window boxes? It mainly depends on your sun exposure. See our list of flowering window box plants that love sun—and shade.
Window boxes are great for houses and apartments with balconies—as well as businesses and restaurants. Growing plants in window boxes puts them at eye level, which lends a different perspective than having them in your garden. The plants will become part of your view to the outdoors. And from the outside, the plants and container become part of the architecture.
What to Plant in Window Boxes
Wondering what to plant? Petunias, geraniums, zinnias, nasturtiums, and begonias are good choices for main-theme flowers. Fill in with things like wandering jew, ivy, euonymus, heather, or vinca, which will cascade over the edge of the box. Impatiens do well in shady locations. More subtle choices include coleus, heliotrope, and salvia. Window boxes look their best if they’re crowded with plants.
Experienced gardeners can train climbing vines around the window frame for an ensemble effect. Connoisseurs may choose to add topiary forms as a focal point. Ivy or fig-vine standards (“lollipop trees”) or other identifiable shapes can capture the imagination.
Image: Geranium, a classic sun lover.
But the most important considerations are sun exposure and which way your window box faces. The leaves of shade-lovers will get scorched in the high light levels of a south or west-facing wall; plants that thrive in full sun will grow tall and leggy in a northern exposure.
Window Box Flowers for Full Sun
(for a sunny, hot, south or west-facing window)
|opal and bush basil|
|‘Blackie’ sweet potato vine|
|‘Homestead Purple’ verbena|
|miniature climbing rose|
Image: Coleus, a shade-lover
Window Box Flowers for Shade
(for a shady, cool, north-facing window)
|fern (maidenhair, tassel, Boston, asparagus)|
|sweet autumn clematis|
|variegated English or Algerian ivy|
|sweet autumn clematis|
Photo credit: Brandt Bolding/Shutterstock
Often overlooked for window boxes are foolproof flowering bulbs. Whether you do a fall planting of miniature daffodils, snowdrops, or hyacinths for springtime bloom, or you do a late-spring planting of lilies, alliums, or dwarf gladiolus for summertime bloom, be sure to tuck a few bulbs and corms into your window boxes for added impact.
Vegetables and Herbs
If you’ve got an accessible location, try planting edibles. Plant herbs like sage, chives, thyme, and mint. Just open the kitchen window when you need some fresh herbs! Cherry tomatoes, lettuce, and kale mixed with marigolds will do nicely in a window box. Like flowers, they will need water every couple of days and fertilizer every two weeks. (Since a window box is just a breeze away from your living quarters, you might want to avoid aromatic fertilizer like fish emulsion.) Be sure to cultivate the soil regularly so that the water will penetrate throughout rather than just run off.
Building a Window Box
There are many window boxes or troughs sold in garden centers than can be easily mounted or hung on a balcony.
For a house, a wood window box can easily be custom-built to fit the length and width of a windowsill, so wood remains the medium of choice. Its life can be extended significantly by using the box simply as a holder for a metal or plastic planter or for several potted plants. Wood is also the easiest for mounting to your house. A word of caution here—do not set the box directly against the wood of your house. Leave an inch or two of breathing space so that moisture does not build up. And make sure the box is securely fastened to your house.
- Drill some drainage holes and put a one-inch layer of rocks in the bottom of the box. Good drainage is essential. Cover the bottom with a piece of large-mesh hardware cloth before adding the layer of ¾-inch stones.
- Use a standard potting mix from your garden center, or mix your own using soil, peat, sawdust, sand, and a little bonemeal. Add compost for edibles. Fill the box to within an inch of the top. It’s important to enough good potting soil around the plants so they sit firmly.
- Water and mix thoroughly. Add more soil if it has settled, and water and mix some more.
- Make sure to water and fertilize often.
- Don’t be afraid to replace plants that have finished blooming with others.
Do you live in an apartment building or condo? See how to start a balcony, rooftop, or terrace garden!