Best Flowers for Window Boxes — 6 Lively Blooms Pro Gardeners Use to Add Character to a Home's Façade

With the summer season making an appearance, it's key to take care of your colorful blooms, wherever they may be. From blossoming beauties in backyard patios to precious flowers in window boxes — without a doubt, these delicate blooms will add style and character to your home.

When choosing the best flowers for window boxes, it's important to consider one thing and that is: sunlight exposure. Depending on the type of flower, blooms that prefer shade might get scorched in high levels of sun exposure. 'One thing to consider while choosing these flowers for window boxes is the sunlight exposure in your window,' says Kat Aul Cervoni, landscape designer and founder of Staghorn NYC and The Cultivation by Kat. 'Too much light and the plants are susceptible to drying out pretty quickly. So, for folks with extra-sunny exposures, it may be prudent to choose particularly water-savvy plants, such as sedums and succulents, or else watering might be a daily duty.'

So what are the best flowers for window boxes? If you're keen to explore this container gardening practice, we've created an insider guide into charming flowers that will brighten up your space with character and grace.

How to choose flowers for window boxes

Window boxes are a great way to add a decorative touch to the exterior of your home, as well as framing your view out with beautiful flowers and plants. However, as they so directly affect your home's curb appeal, you'll need to choose window box ideas that look good all year round.

That means considering when the plant's flowering season is, whether you're choosing annuals that need to be replaced after they've had their time, or how to plant up perennials that complement each other and ensure interest season after season. You may also want to combine your short-lived annuals or perennials alongside more evergreen offerings, so there's never a moment your window boxes feel unloved.

And, don't forget, not only are window box flowers beautiful to look at, but depending on the type, they can add a luxurious scent into your home.

1. Petunias

Perhaps the most common flower trend spotted blooming in window boxes is the much-loved Petunia. The bright and beautiful florals are a sure-fire way to add some color to the outside of your home. Generally, petunias are easy to care for, but it is essential to remember these annual flowers love a well-drained soil and lots of sunlight.

‘Annuals are probably best for color as they bloom all season long as compared to perennials that go in and out of flower throughout the season,' Diane Blazek from the National Garden Bureau tells us.

Petunias come in a wide range of colors and varieties such as trailing and upright —and depending on your style and preference, you can choose the one that is best suited for you. These delightful blooms are also known to make an appearance throughout the spring and summer. So get ready for these colorful delights in your window boxes!

Hardiness zones: 9 to 11 (According to United States Department of Agriculture)
Soil type: Well-drained, moist
Type: Tender perennials, but are mostly grown as annuals
Sun exposure: At least 6 hours of direct sunlight per day

2. Touch-Me-Not (Mimosa pudica)

Sensitive to the touch, this plant does not pose a lot of hassle, and is a great flower for low maintenance gardens. All it needs is a nice dose of sun for good growth.

'Touch-me-not plants (Mimosa pudica) love lots of sunlight and moist-but-well-draining soil,' says Kat Aul Cervoni, landscape designer and founder of Staghorn NYC and The Cultivation by Kat. 'Place these low-maintenance plants near eastern or south-facing windows for a daily dose of rays to prevent them from closing up and also help with blooming. Be wary of fertilizer-enriched potting soil mixes as they may be too rich for them.'

If you prefer to fertilize it naturally, consider mixing coffee grounds, banana peels, eggshells, and green tea in the potting mix.

Hardiness zones: 7–13
Soil type: Well-draining, Loamy soil
Type: Annual or short-lived perennial
Sun exposure: Provide bright, indirect light

3. Pansies (Viola tricolor var. hortensis)

Pansies are not only one of the best flowers for the window box but are also ideal for the fall season. These are great main-theme flowers and can upgrade the look of your flower beds planted along the window.

'Pansies offer a wide range of vibrant colors and are well-suited to the confined space of window boxes,' says Reese L Robins, a gardening expert at Just Pure Gardening. 'They provide a burst of seasonal color and are relatively easy to care for. Incorporating a mix of other flowers allows you to create visually appealing and ever-changing displays throughout the year.'

One thing to keep in mind before choosing flowers is 'to consider the aesthetic appeal and color coordination to enhance your home's curb appeal,' says Reese.

Hardiness zones: 7 to 10
Soil type: Rich, well-drained
Type: Short-lived perennials
Sun exposure: About 6 hours of partial sun

4. Geraniums (Pelargonium)

Easy to grow, easy to love, and easy to look after, geraniums make for popular urban gardening varieties, and look pretty in hanging baskets.

The vitamin D-loving flower, which is more informally known as cranesbills, is believed to have more than 422 species and it comes in a variety of shades, including red and white, orange and yellow, pink, violet and lilac, so there's something to suit every modern front garden color scheme.

For other sun-loving plants, Diane recommends adding, ‘calibrachoa, geraniums, snapdragons, verbena, lantana and shorter varieties of zinnias and marigolds.’

Hardiness zones: 3-9
Soil type: Well-draining
Type: Most are grown as annuals. However, they are perennials in Zones 10-11
Sun exposure: 4-6 hours of full sunlight a day

5. Rosemary (Salvia rosmarinus)

Don't have room for a herb garden? Create your herb garden from your window sill. Coming in handy for cooking, adding rosemary to your window box will give your sill a hit of greenery and leave a pleasant aroma for anyone walking by. Plus, it's also ideal for all those living the good life in a small backyard.

‘Some herbs like basil and rosemary are good fillers and oregano and thyme as spillers,' says Diane. If you're a fan of herbs, you can also learn how to grow cilantro, which is a great window box addition.

Hardiness zones: Zone 7
Soil type: Well-drained, loamy,
Type: Perennial
Sun exposure: At least six hours of direct sunlight

6. Fuchsias

Does you window get more shade than the sun? Consider adding bright and beautiful shade-loving florals to your window with a perennial like the much-loved fuchsia. These flowers are a big garden trend and look great every year. The exotic-looking flower, which looks like little hanging lanterns, tends to trail (although they can grow upright with a little bit of TLC) making for the perfect addition to hanging baskets.

'Fuchsia aside, perennials that work well in window boxes include varieties like strawberry, sedum, marigold, creeping jenny, pansy, Ivy, and lavender,' says Reese. 'These plants are not only beautiful but also adapt well to the limited space of window boxes. They're known for their resilience and ability to return year after year, making them a cost-effective and low-maintenance choice for window box gardening. Their trailing or compact growth habits add a lovely dimension to your windowsill garden.'

Hardiness zones: Some Fuchsia are tender and tolerate zone 10-11. Others are half-hardy and survive cooler climates in USDA zones 9-10
Soil type: Moist but Well-Drained,
Type: Tender perennials
Sun exposure: Full morning sunlight and afternoon shade

How many flowers should you put in a window box?

‘There are two things one needs to know first to figure out how many flowers are needed,' Diane says. 'First, what size (height and width) are the flowers you wish to use? Secondly, how long and deep is your window box?' gardening expert Laura Janney says.

For a window box, you can position each plant closer together than what the tag or label suggests. Just know that some plants are more aggressive growers so they may outgrow their neighbors.

'A little trial and error goes a long way in learning what works best together but to start, and in general terms, you can place one plant every 6” in a window box, going right to the ends to make the box look full and lush,’ says Diane.

How to make a window box look beautiful?

When planting in a window box, Laura recommends considering the following:

Design Layout: She says you should start with a 'unified base of one plant variety to create cohesion. This establishes a visually pleasing foundation that ties the arrangement together'.

Thriller Plants: Choose more dramatic plants as your 'thrillers.' Laura adds: 'These should be placed in a zigzag or wave pattern in the center of the box to create height and a focal point. Good examples of thriller plants include ornamental grasses, small shrubs, or taller flowers like snapdragons'.

Spiller Plants: Incorporate cascading flowers for window boxes which spill 'over the edges of the box to add dimension and soften the edges. These should be tucked into the corners and dotted along the sides. Popular spillers include petunias, ivy, or sweet potato vines'.

Filler Plants: Another tip is to fill in the gaps between the thrillers and spillers with some 'filler' plants. Laura says 'these should be simpler, colorful plants that add bulk to the arrangement without competing for attention'.

How do I pick the right conditions for flowers in a window box?

Soil and Watering: 'Use high-quality potting soil and ensure your window box has adequate drainage to prevent waterlogging. Consider moisture-control soil to help maintain consistent moisture levels, especially in full sun locations,' Laura says.

Sunlight: It's important to know how much sunlight each plant needs, so 'make sure to understand the light requirements of your chosen plants and the amount of sunlight your window box will receive. Select plants according to whether they need full sun, partial shade, or full shade to ensure they thrive'.

Regular Maintenance: 'Regularly check your plants for watering needs, trim back any overgrown foliage, and deadhead flowers to encourage new growth. This will keep your window box looking lush and healthy throughout the season,' Laura adds.

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