Best Choices for Cascading Flowers in Window Boxes

By Guest Author Matthew Buquoi

Cascading flowers are often called spillers or trailing plants because of their beautiful and unique spilling effect in window boxes. Whether you live in the city, suburbs or a rural area, cascading flowers lend a subtle scent and an ethereal ambience to your home.

What To Consider Before Choosing Cascading Flowers

There are a few things that you should consider before selecting spillers.

What kind of window box do you have or would you like to use?

For example, if you have PVC window boxes (or like their function), you most likely want petunias as your spiller. Each flower has a different style, so you might want to check out the different styles before choosing one.

What kind of flowers would match the style of your house?

For example, if you live in a farmhouse or a similar setting, you might want flowers that produce a dramatic effect in your window box. If you live in a modern-style home, perhaps a minimalistic effect would be more appealing.

Which types of trailing plants would look good with the fillers you’ve chosen?

Think about complementary colors like blue and orange or yellow and purple. Or maybe you just want a completely green theme. Think about the different kinds of textures you want to include too.

Are my window boxes in the sun or shade or partially in both?

The amount of sun or shade is pretty important when considering the type of flower you’d like to grow. For instance, petunias love all-day sun, but impatiens need all-day shade. Make sure you choose the right plants for each location.

Do you want to switch out your spillers during the season, or would you rather have something that lasts all year round?

Do you like to tinker with the plants in your window boxes or leave them be all year? Consider whether you’d like to switch your spillers out between seasons.

How often do you want to spend time maintaining your window boxes?

Do you enjoy spending a lot of time maintaining your window box garden? Or are you a next-to-zero maintenance person who would prefer self-watering window boxes?

We’ve discussed some questions to ask yourself before you make any decisions with regard to your spillers and fillers. Here are seven different types of cascading flowers that can be used to liven up your home.

Common cascading or “spiller” flowers for window boxes

Petunias

• Botanical name: Petunia spp.
• Sunlight: About 4 to 6 hours of sunlight a day.
• Watering: The best practice is to drain them freely and keep the soil moist.

Petunias are known for their cheerful and radiant colors that bloom from spring to fall. There are plenty of colors to choose from, ranging from speckled whites to solid, deep pinks and reds. Petunias surprisingly thrive on minimal care. Usually, the Wave and Grandiflora petunia species produce the spiller effect in window boxes. If you’re going with the Wave species, you don’t have to deadhead as much, so you can definitely plant these in hard-to-reach areas like second or third-floor windows.

Nemesia

• Botanical name: Nemesia strumosa or Nemesia caerulea.
• Sunlight: Full sun is preferred for best growing practices.
• Watering: The soil must be moist to the touch but never soggy.

Nemesia produces a multitude of small flowers in an array of vibrant colors depending on which subspecies you choose. For example, the species N. strumosa produces white or blue flowers that are about 1 inch in diameter and grow about a foot tall; these flowers fall in a droopy manner. N. caerulea produces white, blue, purple, or pink flowers. This species grows about 1/2 inch in diameter and about 2 feet tall, and falls in the same droopy manner.

Impatiens

• Botanical name: Impatiens walleriana.
• Sunlight: Full shade.
• Watering: The soil must be moist — the foliage will shed if it’s dried out.

Impatiens (or I. walleriana) produce a wide variety of stunning reds, pinks, purples, and violets. Impatiens will bloom in a beautiful display from spring through summer. They can last all year if you live in a warm area without freezing winters. Most impatiens species grow between 6 inches to 1 foot in length, and they will just ever so slightly peep over the edge of your window box.

Nasturtiums

• Botanical name: Tropaeolum majus.
• Sunlight: Full sun (for optimal growth).
• Watering: The soil should be well drained.

Nasturtium is a climbing/trailing plant that grows impressive vines that will hang effortlessly from window boxes. A fun fact about nasturtiums is that they’re edible! Their seed pods, flowers, and leaves have a mustard and peppery-like taste that makes them a great garnish for salads and other tasty dishes. Nasturtiums bloom from mid-spring to fall and grow about 1 foot long (or a little more) depending on the species.

Begonias

• Botanical name: Begonia semperflorens.
• Sunlight: Partial sun (specifically morning sun and afternoon shade with a dabble of sun).
• Watering: The soil should be evenly moist.

Begonias are charming flowers of many shapes and sizes that bloom in reds, yellows, pinks, oranges, and whites. Begonias are deer resistant, so you don’t have to worry about them being eaten if you live in a rural area where deer are roaming.

Pansies

• Botanical name: Viola tricolor var. hortensis (name of Viola x wittrockiana species).
• Sunlight: Full sun or partial sun.
• Watering: Well-drained soils are best for optimal growth.

Pansies are also called violas and violets. Depending on the species, they bloom delightfully in various hues of red, purple, blue, pink, yellow, orange, white, and mahogany. Pansies can be treated either as an annual or perennial spiller depending on your climate. They often can survive a harsh freeze in single-digit temperatures, which is pretty incredible. They can grow about 6 to 9 inches tall and spread to about 9 to 12 inches.

Lobelias

• Botanical name: Lobelia spp.
• Sunlight: Full sun is preferred, but they can also tolerate partial sun.
• Watering: The soil must be moist for best growing practices.

Lobelias are carefree and super-easy-to-grow spillers that come in lovely pinks, dark purples, blues, whites, and lavenders. Although most varieties of this species are pretty compact, growing between 3 to 5 inches, some species actually grow up to 3 feet tall, making them perfect for window boxes. Lobelias bloom from summer up until the first frost in the fall. Blue flowers only make up 10% of the entire plant kingdom, so these rarities are perfect to add a unique look to your window box garden!

Author’s Bio: Matthew Buquoi is the founder and CEO of Flower Window Boxes and has spent his life pouring his passion for home improvement, gardening, and lawn care since 2008. Matthew is well-known for his features in multiple magazine covers and TV spotlights, such as, HGTV, The Today Show, and Ask this Old House.