The Best Trailing Plants for Window Boxes

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Window boxes are a great way to add a touch of nature to your home, even if you don't have a garden or outdoor space. These small containers can be mounted outside windows or on balcony railings, creating a beautiful display of plants and flowers that can be enjoyed from both inside and outside your home.

Window boxes come in a variety of shapes, sizes, and materials, and can be filled with different types of plants, depending on your personal preferences and the amount of sunlight your window box receives. But choosing the right plants for your window boxes is crucial to ensure their success.

Here we'll focus on trailing plants for window boxes, which are perfect for adding a cascading effect to your display. Trailing plants are cascading plants that grow downward, spilling over the edges of the container and creating a lush and vibrant display.

We'll discuss the benefits of using trailing flowers in your window boxes and provide examples of some of the best trailing plants to use. We'll also share some tips for plant care, watering, and maintaining your window box, as well as how to combine different trailing plants for a stunning display.

To learn more about growing flowers in containers, check out my guides:

Container Color: Easy Steps to Growing Bulbs in Pots

Container Cosmos: How to Grow Cosmos in Small Spaces

Petunias trailing plants for window boxes

Cascading Flowers for Window Boxes

Trailing plants are those that have a growth habit of cascading downward, instead of growing upright like a tree or bush. These plants often have long stems that branch out and produce leaves, flowers, or both along their length.

Trailing plants have several characteristics that make them ideal for window boxes. They often have a profuse blooming habit, which means they produce an abundance of cascading flowers throughout the growing season.

They are also typically low-growing, so they won't obstruct your view out of the window. Trailing plants are also easy to care for and can be pruned to maintain their shape and size.

There are several advantages to using trailing plants in window boxes. First, they add a beautiful cascading effect to your display, creating a sense of depth and dimension.

Second, trailing plants can help soften the look of a window box, making it appear more natural and organic. Third, they can help hide the container itself, which can be especially useful if your window box is made of a less attractive material.

Fourth, trailing plants can create a sense of privacy for your home, as they can partially block the view into your window. Finally, trailing plants are often low-maintenance, making them ideal for busy gardeners.

1. Petunias

  • Profuse Blooms:

    Petunias are known for their abundant and long-lasting blooms, which can add a burst of color and beauty to your window box display throughout the growing season.

  • Easy Maintenance:

    Petunias are relatively easy to care for and require minimal pruning and deadheading to maintain their shape and health.

    To learn more about growing petunias, check out my guide How to Fertilize Petunias So They Bloom Like Never Before.

  • Versatility:

    Petunias come in a wide range of colors and varieties, making it easy to find the perfect plant for your window box display.

    They can also be mixed with other trailing plants to create a visually interesting and cohesive look.

  • Tolerant of Sun and Heat:

    Petunias thrive in full sun and warm temperatures, making them ideal trailing plants for window boxes full sun.

  • Attract Pollinators:

    Petunias are known to attract bees, butterflies, and other pollinators to your garden, helping to support the local ecosystem and promote biodiversity.

My recommended petunia seeds:


Lobelia trailing plants for window boxes

2. Lobelia

  • Delicate and Beautiful Blooms:

    Lobelia produces delicate, bell-shaped blue flowers.

    Their small size adds a charming and elegant touch to any window box display.

  • Easy Maintenance:

    Lobelia is a low-maintenance plant that requires minimal pruning and deadheading to maintain its shape and health.

  • Attractive to Hummingbirds and Butterflies:

    Lobelia is known to attract hummingbirds and butterflies to your garden, making it a great option for those who want to create a wildlife-friendly window box display.

  • Tolerant of Shade:

    Lobelia can tolerate partial shade, making it a good option for window boxes that don't receive direct sunlight.

  • Versatile:

    Lobelia can be used on its own or mixed with other trailing plants to create a visually interesting and cohesive look.

My recommended lobelia seeds:


3. Ivy

  • Evergreen Foliage:

    Ivy is an evergreen plant, meaning it retains its leaves throughout the year, providing a year-round greenery in your window box.

    Ivy is an excellent evergreen trailing plants for window boxes.

    Learn more about other low maintenance evergreen plants for pots in our guide here.

  • Tolerant of Different Light Conditions:

    Ivy can tolerate both sun and shade, making it a great option for window boxes that receive varying amounts of sunlight throughout the day.

  • Low-Maintenance:

    Ivy is a low-maintenance plant that requires minimal pruning and care to maintain its shape and health.

  • Versatility:

    Ivy comes in a variety of leaf shapes, sizes, and colors, making it easy to find the perfect plant for your window box display.

    It can also be mixed with other trailing plants to create a visually interesting and cohesive look.

My recommended ivy plants:


Nasturtium trailing plants for window boxes

4. Nasturtium

  • Beautiful and Edible Flowers:

    Nasturtium produces bright and colorful flowers in shades of orange, yellow, and red.

    These flowers are not only beautiful, but also edible and can be used to add a unique flavor to salads and other dishes.

  • Easy to Grow:

    Nasturtium is an easy-to-grow plant that is ideal for novice gardeners.

    It grows quickly and requires minimal care to thrive. It is also known to be deer resistant.

    Nasturtiums are also popular companion plant for many vegetables, including cauliflower.

    They are attractive to many beneficial insects, including aphid-eating ladybugs and hoverflies.

    Read more about using nasturtiums as a companion plant for vegetables like cauliflower here.

  • Attracts Pollinators:

    Nasturtium is known to attract pollinators, such as bees and butterflies, to your garden.

    This can help to support the local ecosystem and promote biodiversity.

  • Tolerant of Poor Soil:

    Nasturtium can tolerate poor soil conditions, making it a good option for window boxes that may not have the best soil quality.

  • Versatile:

    Nasturtium can be grown in a variety of different ways, including as a trailing plant in a window box, as a climbing plant on a trellis or fence, or as a groundcover in a garden bed.

My recommended nasturtium seeds:


Sweet Potato Vine Trailing Plants for Window Boxes

5. Sweet Potato Vine

  • Vibrant Foliage:

    Sweet potato vine is known for its vibrant and colorful foliage in shades of green, purple, and even pink.

    Its leaves are shaped like hearts or lobes, which can add an interesting texture to your window box display.

  • Fast Growing:

    Sweet potato vine is a fast-growing plant that can quickly fill up your window box with its lush foliage.

  • Tolerant of Heat and Sun:

    Sweet potato vine is tolerant of heat and sun, making it a great option for window boxes that receive a lot of direct sunlight.

  • Easy to Propagate:

    Sweet potato vine is easy to propagate by taking stem cuttings, which makes it a great option for creating more plants for your window box or sharing with friends.

  • Versatile:

    Sweet potato vine can be grown in a variety of different ways, including as a trailing plant in a window box, as a groundcover in a garden bed, or even as a climber on a trellis.

My recommended sweet potato vine:


My Top Picks for Window Boxes

Tips for Using Trailing Plants in Window Boxes

Planting Tips:

  • When choosing your plants, consider their growth habit and the amount of sunlight your window box receives. Make sure to choose plants that will thrive in your specific conditions.

  • To ensure good drainage, add a layer of gravel or broken pottery to the bottom of your window box before adding soil.

  • Fill your window box with good quality potting soil that is rich in nutrients. Here is my recommended organic potting soil.

  • Place your trailing plants towards the edge of the window box so that they can spill over the sides.

Watering and Fertilizing Tips:

  • Water your window box regularly, as plants in containers dry out more quickly than those planted in the ground. Check the soil regularly and water when the top inch is dry to the touch.

  • Fertilize your plants with a slow-release fertilizer or a liquid fertilizer according to the package instructions. Here is my recommended slow release fertilizer.

  • Be careful not to overwater, as this can lead to root rot and other issues.

Pruning and Maintaining Tips:

  • Prune your plants regularly to maintain their shape and encourage healthy growth.

  • Remove any dead or yellowing leaves to prevent disease. Deadheading geraniums, for example, is an essential practice for promoting new growth and encouraging geraniums to produce more blooms. Read more here about how to deadhead geraniums.

  • Pinch back the tips of your plants to encourage bushier growth.

  • If your plants become too leggy, trim them back to encourage new growth.

Combining Different Trailing Plants:

  • Choose plants that have similar light and water requirements.

  • Combine plants with different colors and textures to create a visually interesting display.

  • Group plants with similar growth habits together for a more cohesive look.

  • Consider using a variety of trailing plants with different blooming times to ensure that your window box looks beautiful throughout the growing season.

Trailing plants are a fantastic option for container gardening especially in window boxes, offering a variety of benefits including a cascading effect, softening of the container's look, privacy, and low-maintenance care.

When choosing trailing plants for your window box, consider their growth habits, light requirements, and colors to create a visually appealing and cohesive display throughout summer.

Trailing plants in window boxes can add a sense of depth and dimension, soften the look of the container, and enhance curb appeal. To get the most out of your trailing plants, make sure to properly plant them, water and fertilize them regularly, and prune them to maintain their shape and health.

By following these tips and guidelines, you can create a stunning window box display that adds beauty and life to your home. With proper care and consideration, your trailing plants can thrive in your window box and provide you with a beautiful display for years to come.

Looking for more container gardening inspiration? Check out my container gardening guides: