Why don’t people plant window boxes? This is a question I often ask myself on Saturday mornings at my garden center. There’s usually no shortage of excited gardeners filling carts with assorted container plants, but these plants usually don’t end up in a window box. They, instead, find their way into a large patio pot or entryway container. I’ve found that most gardeners like the way that window boxes look. Whether perched on a sill or draped across a threshold, they add charm to the outside of a home. But designing one that looks good and thrives in its location can be a challenge. As a container, a window box is unforgiving: Forget to water a few times or use the wrong plants and it’s “game over.” Creating a successful window-box design is mostly about plant choice, but proper placement and selecting the right soil and fertilizer is important, too. These designs prove that there is a window box to fit almost everyone’s situation.
For those with no time to deadhead
- ‘Snoopy’ begonia (Begonia ‘Snoopy’, USDA Hardiness Zones 10–11)
- Golden variegated sweet flag (Acorus gramineus ‘Ogon’, Zones 6–9)
- Molten Lava™ oxalis (Oxalis vulcanicola ‘Molten Lava’, Zones 9–11)
- Horsetail rush (Equisetum hyemale, Zones 3–11)
- Twist and Twirl® coleus (Solenostemon scutellarioides ‘Twist and Twirl’, Zone 11)
- ‘Red Ruffles’ coleus (Solenostemon scutellarioides ‘Red Ruffles’, Zone 11)
- ‘Polly’ elephant’s ear (Alocasia ‘Polly’, Zone 11)
- ‘Black Coffee’ begonia (Begonia ‘Black Coffee’, Zone 11)
- ‘Ruby Red’ alternanthera (Alternanthera dentata ‘Ruby Red’, Zone 11)
Let’s face facts: Flowers are beautiful, but they take work. To keep most annuals in bloom, you need to deadhead—a lot. And that’s not always convenient with a window box that is hanging out of reach. With this combination, you get all the color and interest of a box filled with blossoms but without the headache of high maintenance. I chose plants that have exotic-looking leaves, such as ‘Polly’ elephant’s ear and the two colorful coleus. (You’ll need to pinch the coleus periodically throughout the season, however, to keep them from taking over this partial-shade combination.) A biweekly application of an all-purpose liquid fertilizer is all that’s necessary to maintain this box’s good looks.
If you’re out of room for veggies
- Lemon grass (Cymbopogon citratus, Zones 10–11)
- Golden sage (Salvia officinalis‘Aurea’, Zones 5–8)
- ‘Pesto Perpetuo’ basil (Ocimum × citriodorum ‘Pesto Perpetuo’, annual)
- ‘Sparkler’ pepper (Capsicum annuum ‘Sparkler’, annual)
- ‘Zebrina’ banana (Musa acuminata ‘Zebrina’, Zone 11)
- ‘Bright Lights’ Swiss chard (Beta vulgaris ‘Bright Lights’, annual)
- Rosemary (Rosmarinus officinalis, Zones 8–11)
- Bloodydock (Rumex sanguineus, Zones 6–8)
- Dwarf pomegranate (Punica granatum* var. nana, Zones 7–10)
- ‘Red Malabar’ spinach (Basella rubra, annual)
- Golden edge thyme (Thymus vulgaris ‘Aureus’, Zones 4–9)
If you love the idea of having a vegetable garden but don’t have the space or can’t commit to creating a large bed, try this combination that is not only beautiful but also 100 percent edible. A variegated basil gives the planting height in the back, while a hot pepper with similar variegation makes the middle ground pop. ‘Red Malabar’ spinach provides a classic spiller for the container. The edibles can be continually harvested by trimming the plants weekly throughout the season. Use an organic container mix with the addition of a few handfuls of compost, and make sure the box receives at least six to eight hours of direct sunlight. With a weekly application of fish emulsion, this window box will feed you and look fabulous all summer long.
To amp up an area of low impact
- ‘All Gold’ Japanese forest grass (Hakonechloa macra ‘All Gold’, Zones 5–9)
- ‘Freckles’ coleus (Solenostemon scutellarioides ‘Freckles’, Zone 11)
- Luscious® Citrus Blend™ lantana(Lantana camara* ‘2003.301’, Zones 9–11)
- Persian shield (Strobilanthes dyerianus, Zones 9–11)
- Purple velvet plant (Gynura sarmentosa, Zones 10–11)
- Golden creeping Jenny (Lysimachia nummularia* ‘Aurea’, Zones 4–8)
- Farfugium (Farfugium japonicum, Zones 7–8)
- ‘Swallowtail’ coleus (Solenostemon scutellarioides ‘Swallowtail’, Zone 11)
- ‘Sedona’ coleus (Solenostemon scutellarioides ‘Sedona’, Zone 11)
- Bird’s-nest fern (Asplenium nidus, Zone 11)
- Croton (Codiaeum cv., Zone 11)
An uninteresting space (like the sill of this toolshed) needs a bold design to enhance its look. To do this, I like to rely on a composition of compelling textures and hot colors. The shiny leaves of the farfugium in this window box demand attention due to their smooth and glossy texture, while the fiery-colored foliage of the croton provides additional pop. Maintaining this partial-sun design is easy: Pinch the coleus to keep it in check, and deadhead the lantana so that it stays in bloom. Tropicals, like the ones in this design, do best when planted in a soil that contains slow-release fertilizer and is kept consistently moist.
To avoid rot in a moist and shady spot
- ‘Purple Knight’ alternanthera (Alternanthera ‘Purple Knight’, annual)
- ‘Inky Fingers’ coleus (Solenostemon scutellarioides ‘Inky Fingers’, Zone 11)
- ‘Wild Pony’ Rex begonia (Begonia ‘Wild Pony’, Zone 11)
- ‘Mojito’ elephant’s ear (Colocasia esculenta* ‘Mojito’, Zones 8–11)
- Ribbon plant (Homalocladium platycladum, Zone 11)
- Tiger fern (Nephrolepis exaltata, Zone 11)
- ‘Gold Lace’ coleus (Solenostemon scutellarioides ‘Gold Lace’, Zone 11)
North-facing areas present a number of problems for a window box. Because there’s not a lot of sun, these spots tend to be supermoist, which can lead to rotting plants. There’s no risk of rotting, however, with this two-color design because these plants love moisture. Planting the large speckled ‘Mojito’ elephant’s ear at the back of the box provides room to snuggle in several more plants below it—plants that need a little extra shade to thrive. The tiger fern adds a dash of bright color to contrast with the dominant dark tones. I purposely chose a black window box so that it would completely disappear in a shady spot and enable the true stars—the plants—to shine. Be sure to use a container mix with slow-release fertilizer because this box contains heavy-feeding tropicals.
Tip: Get the Fertilizer Right
In a shallow window box, there is little soil, so watering needs to be more frequent and nutrient deficiency is more of a problem than with larger containers. Fertilizing is essential for achieving good-looking window boxes. But not all plant food is the same, so be sure to choose the right one.
Time-release granular fertilizer
When to use it: On heavy-feeding plants, such as tropicals
When not to use it: If your potting soil already has it mixed in
Liquid Fish Emulsion
When to use it: On edibles because it’s a good organic alternative to all-purpose synthetics; on salt-sensitive plants, like palms
When not to use it: If plants are overly stressed because the effect won’t be quick enough to help; if rodents are a nuisance in your area because they will be attracted to the fishy smell
Liquid All-Purpose Fertilizer
When to use it: On anything; a biweekly dose maintains average plant health
When not to use it: During the hottest or sunniest part of the day because accidental splashing from the salt-based formula can cause foliage burn
Blossom-booster liquid fertilizer
When to use it: On heavy-flowering annuals or on tropicals that refuse to reflower
When not to use it: On foliage plants that don’t set flower buds
Pomegranate (Punica granatum)
This plant is considered invasive in CA.
Lantana (Lantana camara)
This plant is considered invasive in AZ, FL, HI, SC, and TX.
Creeping Jenny (Lysimachia nummularia)
This plant is considered invasive in AZ, FL, HI, SC, and TX.
Elephant’s ear (Colocasia esculenta)
This plant is considered invasive in FL.
Please visit invasiveplantatlas.org for more information.
Sarah Partyka owns The Farmer’s Daughter, a nursery in South Kingstown, Rhode Island.
Photos, except where noted: Danielle Sherry.
From Fine Gardening #140