Planting the Perfect Windowbox

How to Plant a Window Box

The first step in planting a flower box is to choose your box and where you want to hang it. Don't underestimate how heavy a window box can be—it is filled with soil and plants and gets even heavier when watered. It is recommend buying or building a sturdy box made of a hardwood like redwood or cedar rather than pine (which rots quickly) and then hanging the box with a set of window box brackets.

Always make sure your window box has drainage holes. To aid drainage, place 2 inches of nonbiodegradable packing peanuts or old wine corks in the bottom of the box, and then cover with landscape fabric to prevent soil from seeping out. DO NOT USE GRAVEL - IT WEIGHS TOO MUCH!! Like most of us, excess weight is not your friend.

Next, fill the box halfway with potting mix, and add your plants. DO NOT USE TOPSOIL - it will compact and once again is heavier than potting mix. Make sure your plants are placed a few inches apart to give them room to fill out. If you want immediate impact, you can plant closer, of course, but know that you will need to pinch or prune your plants to prevent overcrowding. Once your plants are in place, fill in the gaps with more soil and lightly pat down around the plants and water thrououghly.

As with all container plantings, choose plants with similar water and light needs, and expect to water them more often than those in the ground. Water thoroughly once the soil has dried out. You’ve watered enough when the water comes out the bottom drain holes.

What to Plant in Window Boxes

Most successful window boxes contain a mix of these three primary plant types. These are some of the better know and available favorites in each category. This list is only a suggestion, let your imagination run wild…

Thriller

They are your hero plants—the ones that command attention and drive the rest of the design. These are planted in the back row of the box and are planted first.

Sunny:

Dwarf Cannas, Celosia, Dracaena, Pink Fountain Grass, Geraniums, Nicotiana, Papyrus, Purple Fountain, Coleus

Shady:

Caladium, Coleus, Cordyline, Dracaena, Fuchsia, Impatiens, New Guinea Impatiens

Spillers

Trailing over the side of the container, these plants add softness and a little romance. These plants are planted second, and in the front of the box so that they can cascade.

Sunny:

Asparagus Fern, Fiber Optic Grass, Ivy Geranium, Lantana, Lotus, Supercascade, Petunia, Sweet Potato Vine, Thyme, Trailing Petunia, Trailing Vinca, Verbena, Vinca Minor

Shady:

Asparagus Fern, Creeping Jew, Creeping Wire Vine, Dragon-wing Begonia, Licorice Vine Ivy, Geranium Ivy, Variegated & Green Lamium, Bridal Veil Wave, Torenia Vinca Vine

Fillers

Midsize plants bridge the space between thrillers and spillers. These are planted last to fill in the blanks between the other plants.

Sunny:

Cosmos, Dusty Miller, Eucalyptus, Geraniums, Gerber Daisy, Joseph’s Coat, Petunia, Salvia, Coleus, Vinca, Zinnia

Shady:

Begonias, Boston Fern, Caladium, Coleus, Dragon-wing Begonia, Dusty Miller, Hosta, Impatiens New Guinea, Pansy, Rex Begonias, Salvia

5 Window Box Design Tips

Keep in mind a few basic design principles, then unleash your creativity.

1. Use Repetition in Your Planting

Repetition is a foolproof way to create a cohesive look in a window box. This works best for longer boxes where the pattern shows.

2. Choose a Focal Point

Choosing the centerpiece first means the rest of your plant picks will fall into place. Choosing a single slightly taller plant with a unique color or shape in the back center of the box creates a focal point.

3. Think About Texture

It’s not always about the flowers. Textured or colorful leaves create a great impact as well.

4. Take Cues from the Landscape

Allow your window boxes be an extension of your landscape beds. Use the same colors or textures to create a harmonious plan.

5. Stay Consistent

Try choosing a single-color palette for all plantings around your house.

Plant Window Boxes with Confidence

If you remember to include a thriller, spiller, and filler that all have the same light requirements, you can assemble a full, colorful window box. Keep garden design elements in mind on a smaller scale and give your box plenty of water to keep the plants happy all summer long.